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WOOD  PATTERN -MAKING 

The  Fundamental  Principles  and  Elementary 

Practice  of  the  Art.     To  which  is 

added  an  appendix  on  the  Care 

and  Use  of  Woodworking, 

(Bench)    Tools. 


BY 

HORACE  TRAITON  PURFIELD 

Instructor  in  Woodwork  and  Pattern  Making,  in  the 
Department  of  Engineering 

OF  THK 
UNIVERSITY    OF    MICHIGAN 


PUBLISHED  BY  THB  AUTHOR 


1906 

rllE   SCHARF  TAG,   LABEL   &   BOX   CO. 
YPSILANTI.  MICH. 


InN  1907 


COPYRIGHT,  1906,  BY 
HORACE  TRAITON  PURFJEI.D 


TS 
'C..-VC 

?ll,1w 

PREFACE 

An  experience  of  seventeen  years  in  teaching  pat- 
tern-making and  kindered  subjects  has  made  me  feel 
the  great  need  of  such  a  work  as  this  which  I  now  offer 
as  a  text -book  for  students  in  technical  and  manual 
training  schools,  and  universities.  A  number  of 
excellent  books  on  the  subject  have  been  published,  to 
be  sure,  but  most  of  them  assume  on  their  reader's  part 
previous  acquaintance  with  the  fundamental  ideas  of 
pattern -making;  such  as  do  treat  at  all  of  the  elementary 
part  of  the  subject,  happen  to  be  works  of  an  exhaustive 
character,  which  are  consequently  too  expensive  for  use 
as  text -books.  The  present  work,  therefore,  will,  it  is 
hoped,  find  a  field  of  usefulness  for  itself. 

It  is  of  course  to  be  recognized  that  as  pattern -mak- 
ing is  an  art,  it  cannot  be  learned  simply  by  reading  any 
book  on  the  subject;  but  only  by  practice.  Still  a  text- 
book may  afford  valuable  assistance  even  to  the  artisan. 
This  work,  however,  has  a  further  and  more  important 
purpose, — that  of  imparting  to  the  engineer  or  the  drafts- 
man the  fundamental  principles  of  pattern -making.  For 
only  as  he  is  in  possession  of  these  can  he  make  designs 
for  patterns  in  accordance  with  which  shop  work  can  be 
performed  in  the  most  efficient  and  most  economical 
manner.  The  reader  should  also  understand  that  this 
work,  being  designed  only  as  an  elementary  treatise,  in 
no  way  exhausts  the  subject.  It  is  claimed  however, 
that  the  examples  of  pattern -making  submitted  indicate, 
on  the  whole,  the  best  methods  of  construction  and  those 
most  easily  understood  by  the  student. 


VI  PREFACE 

In  preparing  the  body  of  this  work,  I  have  received 
many  valuable  suggestions  which  have  been  incorporated 
herewith,  and  which  will  have  contributed  to  any  success 
the  book  may  attain.  The  works  of  many  previous 
writers  on  the  subject  have  been  consulted  also;  for 
specific  ideas  derived  from  them  credit  should  be  given 
to  Joshua  Rose,  M.  E.,  J.  McKim  Chase,  and  P.  S. 
Dingey.  In  preparing  the  appendix  considerable  help 
was  afforded  me  by  the  little  book  of  W.  F.  M.  Goss, 
on  "Bench  Work  in  Wood."  With  these  few  words  of 
introduction,  I  leave  the  book  to  its  readers  with  the 
hope  that  it  will  assist  them  to  master  the  important 
subject  of  which  it  treats. 

H.  T.  P. 


CONTENTS 


*.HAr. 

PREFACE       .... 

PAGE 

LIST  OF  ILLUSTRATIONS         .... 

.     VIII 

I.    INTRODUCTION     

1 

II.    MOLDING     ..... 

jpHEII.    GENERAL  PRINCIPLES 

.       12 

IV.    MATERIALS          

.       20 

V.    FILLETS       

.       30 

VI.    CORES          .... 

37 

VII.    MOLDER'S  JOINTS  OR  PARTINGS 

46 

VIII.    CONSTRUCTIONAL  JOINTS    . 

55 

£JX.    SPECIAL  TYPES  OF  PATTERNS    .... 

.       66 

X.    PLATE  WORK  AND  IRREGULAR  PARTING  . 

83 

i^^l.    PULLEY  PATTERNS      .... 

93 

<£--XII.    PATTERNS  FOR  CAST  GEARS       .... 

.     108 

XIII.    PIPE  FITTINGS     

.     126 

XIV.    MISCELLANEOUS          .... 

.     132 

STOVE  PATTERN  -MAKING           .... 

.     145 

APPENDIX 

READING  MECHANICAL  (WORKING)  DRAWINGS   . 

.     154 

LUMBER   .... 

1  £.1 

PATTERN  TURNING          • 

1  0  1 

.     199 

PLANES  AND  PLANE-  LIKE  TOOLS 

.N    188 

CUTTING  WEDGES    . 

1QC 

BORING  TOOLS         

*          l^v) 

.     181 

SAWS Ill 

INDEX ^  212 


LIST    OF    ILLUSTRATIONS 


FULL    PAGE 


"Oliver"    Combination    Lathe 

Wood  L: 

—Frontispiece 

Rest, 

"Oliver"  Bandsaw,  82 

Universa 

"Oliver"  Handjointer,  36 

Univers£ 

"Oliver"  Trimmers,  97. 

William 

Bed  of  Trimmer.  98. 

"Rogers 

"Crane"  Core  Box  machine,  45. 

IN  THE   TEXT 

FIG. 

FIG. 

1.  Cylinder,  with  coreprints,  6 

22.  Holl 

2.  Holder's  Flask,  7 

be 

3.  To  illustrate  "draft,"  14 

23.  Buil 

4.  Coefficientsof  shrinkage,  16 

24.  Buil 

5.  Screws  in  end  wood,  28 

25.  Thir 

6.  Fillets  sqr.  corner,  31 

ri 

7.  Fillets  round  corner,  31 

26.  Ope 

8.  Pattern  with  square  hole,  38 

27.  Ope 

9.  Mold  made  from  No.  8,  38 

er 

10.  Core  and  full  box,  39 

28.     Op 

11.  Different  size  core  prints,  41 

29.  Lag 

12.  Tapercore  print  system,  44 

in 

13.  (a)  Section  of  a  mold,  47 

30.  Lag 

14.  Single  flange  wheel,  47 

la 

15.  Double  flange  wheel,  48 

31.  Lag 

16.  Worm  wheel,  48 

32.  Ann 

17.  Hook  lever,  49 

33.  Squ 

18.  Small  bracket,  50 

6 

19.  Loose  pieces  skewered  on,  50 

34.  Squ 

20.  Hollow     cylindrical     cast- 

35. Ron 

ing,  51 

36.  Gla 

21.  Hollow     cylindrical      pat- 

36.   (a) 

ern,  51 

c 

Wood  Lathe  with  Compound 

Rest,  54. 

Universal  Sander,  29. 
Universal  Bench  Saw,  65. 
Williamsport  Scroll  Saw,  65. 
"Rogers"  Double  Surfacer,  153 


Hollow     cylindrical     core- 
box,  52 

Built  up  disc,  56 

Built  up  disc  edge,  56 

board    and     counter 
ribs,  57 

Open  joints  cylinder  hd.,  58 

Open  joints  boxing  up  pat- 

erns,  58 
Open  joints  up  corner,  58 

Lagged   or   staved  up  cyl- 
inder, 60 

Lagged  up  cylinder  narrow 
lags,  61 

Lagged  up  core  box,  61 

Annular  pattern,  62 

Square  frame  (plate  work), 
63 

Square  frame  (plate  work), 

Round  corner,  64 

Gland  (the  casting) ,  67 
(a)  Gland   leaving  its  own 
core,  69 


ILLUSTRATIONS 


IX 


37.  Gland  Pattern,  67 

38.  Gland  core  box,  71 

39.  Laying  out  core  box,  71 

40.  Core  box  plane,  72 

41.  Core  box  plane  with  guide, 

73 

41.  (a)  Conical  core  box,  74 

42.  Chuck  with    pieces    nailed 

on,  76 

43.  Cylinder  with  flange   both 

ends,  77 

44.  Cylinder    with   flange  both 

patterns,  77 

45.  Cylinder  with  flange    (core 

box),  77 

46.  Pump  standard  (casting),  84 

47.  Pump  standard  (pattern),  86 

48.  Core  prints  for  No.  47,  88 

49.  Core  box  for  No.  47,  89 

50.  A,  Turning  bosses,  90 

50.  B,  Hook  lever  drawing,  91 

53.  Pulley,  93 

54.  Shoot  board,  96 

55.  Center  of  spider,  100 

56.  Three  armed  chuck,  109 

56.  A,  Foim  of  gear  rim,  110 

57.  Methods    of    forming    gear 

teeth,  112 

58.  Box    for     laying    out    gear 

teeth,  113 

59.  Laying  out  No.  58,   113 

60.  Laying  out  tooth  curves,  117 

61.  Bevel  gear  lay  out,  121 


62.  Chuck,  122 

63.  Chuck,  large,  123 

64.  Pipe  bend,  126 

65.  Pipe  bend,  127 

66.  Pipe  bend,  127 

67.  Pipe  bend,  128 

68.  Pipe  bend,  128 

69.  Pipe  bend,  128 

70.  Pipe  bend,  core  box,  128 

71.  Pipe  bend,  core  box,  131 

72.  Pipe  elbow,  129 

73.  Pipe  elbow  ring,  129 

74.  Pipe     elbow    ends    and 

prints,  130 

75.  Pipe   elbow  built  together, 

130 

76.  Pipe  elbow  core  box,  131 

77.  Steam    chest    cover    (cast- 

ing), 132 

78.  Steam  chest  cover  pattern, 
133 

79.  Skeleton  pattern,  134 

80.  Skeleton  pattern  core,  134 

81.  Skeleton   pattern,    boiler 

plate  form,  136 

82.  Gluing  feather  edge  board, 

137 

83.  Piston  ring,  140 

84.  Piston  ring  pattern,  140 

85.  Drill  press  column,  141 

86.  Loose  piece  dovetailed  on, 

143 


APPENDIX 


1.  Pattern-maker's  bench,  167 

1.  (a)Pattern-maker's  vise, 168 

2.  Bench  hook,  168 


FIG. 

3.  Saw-horse,  169 

4.  Two-foot  rule,  170 

5.  Framing  square,  171 


ILLUSTRATIONS 


6.  Try  square,  171       \ 

7.  Combination  square,  172 

8.  Bevel,  172 

9.  Laying     out     angles    with 

dividers,  173 

10.  Marking  guage,  174 

11.  Mortise  guage,  174 

12.  Tanged  firmer  chisel,  175 

14.  Socket  firmer  chisel,  175 

15.  Inside  gouge,  176 

16.  Outside  gouge,  176 

17.  Sweeps  of  guages,  177 

18.  Draw  shave,  177 

19.  Handsaw,  178 

20.  Backsaw,  178 

21.  Keyhold  saw,  178 

22.  Compass  saw,  178 

23.  Ripsaw  teeth,  180 

24.  Cross-cut  teeth,  180 

25.  Auger  bit,  182 

26.  Square  hole  auger,  182 

26.  (a)   Countersink    drill   bit, 

182 

27.  Syracuse  drill  bit,  183 

28.  Expansive  bit,  183 

29.  Forstner  bit,  183 

30.  Center  bit,  183 

31.  Countersink,  184 

32.  Bit-brace,  185 

32.  (a)  Screwdriver,  185 

33.  Miter  box,  186 

34.  Handscrew,  187 


35.  Iron  clamp,  187 

36.  Iron  plane  with  single  iron, 

190 

37.  Iron     plane     with    double 

iron,  191 

38.  Wood    plane    with    double 
,  ?»  -    iron,  191 

39.  Jackplane,  192 

40.  Blockplane,    192 

41.  Rebate  plane,  193 

42.  Plow  plane,  193 

43.  Dado  plane,  194 

44.  Spoke  shave,  194 

45.  Spoke  shave,  round,  195 

46.  Grinding  a  cutting  wedge, 

197 

47.  Turning  lathe,  200 

48.  Fork  center,  201 

49.  Screw  chuck,  202 

50.  Cup  chuck,  203 

51.  Turner's  gouge,  204 

52.  Turner's  chisel,  204 

53.  Group  of  scrapers,  205 

54.  Core  box  plane,  195 

55.  Use  of  turn  ing  gouge,  206 

56.  Use    of    turning    or    skew 

chisel,  207 

57.  Use  of  turning  chisel  (two 
positions),  208 

58.  Scraping  a  cylinder,  209 

59.  Outside  caliper,  210 

60.  Inside  caliper,  210 


CHAPTER  I. 
/  6,  8  O  S 

INTRODUCTION 

A  pattern  may  be  defined  as  a  model  about  which  is 
to  be  formed  a  sand  mold,  in  which  a  casting  is  to  be 
made.  It  is  usually  of  wood  or  metal,  and  often  con- 
structed in  several  parts  so  as  to  facilitate  removal  from 
the  mold.  In  the  foundry  and  machinery  business  the 
word  pattern  is  understood  to  mean  any  form  or  device  by 
the  use  of  which  a  mold  may  be  made.  Pattern -making 
differs  from  all  other  wood -work  in  several  ways.  The 
product  of  the  pattern  shop  becomes  a  part  of  the  tools 
or  working  outfit  of  another  workman,  viz.,  the  molder. 
The  joiner,  in  making  a  door,  makes  it  just  the  size 
required  by  the  drawing  or  specifications;  the  cabinet- 
maker does  the  same  when  called  upon  to  make  a  table 
or  other  piece  of  furniture;  the  carpenter  also  follows 
this  same  idea  when  building  a  bridge.  In  all  these,  the 
ultimate  object  is  reached  when  the  work  is  complete. 
It  is  not  so,  however,  with  the  pattern-maker;  his 
product  is  only  one  step  in  arriving  at  the  desired  end. 
that  end  being  the  production  of  one  or  more  castings  of 
some  kind  of  metal.  Allowances  must  be  made  in  con- 
structing a  pattern,  that  do  not  have  to  be  considered 
in  other  wood -work;  the  principle  of  these  allowances 
are  for  draft,  shrinkage  of  the  metal  of  the  casting,  and 
the  machining  of  the  casting  where  required.  A  pattern- 


2  WOOD   PATTERN   MAKING 

maker  must  be  a  good  wood-worker,  and  able  to  work 
wood  to  accurate   dimensions,  both   on  the  bench  and  in 
the  lathe,  as  pattern -making  consists  largely  of  fitting, 
joining,  and  making  circular  and  other  forms  to  correct 
size.     This  knowledge  and  ability  are  necessary  to  the 
pattern-maker,   because  a  large  majority  of  patterns  are 
made  of  wood.      The  pattern-maker   must    also   know 
something,  and  the  more  the  better,  of  the  practical  work 
of  the  molder.     This  is  necessary  in   order  that  he  may 
be  able  to  produce  easily-molded  patterns.     He  should 
possess  a  good  practical  knowledge  of  the  properties  of 
metals,   as,  for  instance,   the  contraction  or  shrinkage 
that  these  undergo  in  passing  from  the  molten  to  the  solid 
state,  the  strength  of  cast  metals,  and  also  their  relative 
rate  of  cooling.     He  should  also  thoroughly  understand 
the  principles  of  Orthographic  projection,  so  that,  if  it 
becomes  necessary,    as  is   frequently  the  case,  he   can 
make  full  sized  working  drawings  of  the  work  in  hand. 
The  production  of  ordinary  metal  castings,  such  as 
those  of  iron  or  brass,  involves  three  distinct  operations. 
First,  making  the  pattern;   Second,  from  this  pattern  a 
mold  is  made  in  sand  or  some  other  substance  that   is 
refractory   enough   to  withstand  the    action   of    melted 
metal;  Third,   the  metal  is  melted  and  poured  into  this 
mold.     Each  of  these  operations  require  especial  skill, 
and   has   given   rise    to    a  special    trade,    although   the 
second    and    third,    called   respectively    molding    and 
founding,    are    often   performed   by    the  same    person. 
These  operations  are  sometimes  so  intricate,  and  admit 
of  so  much  variety,  that  the  above  statements    are  only 
true  in  the  main.     Nevertheless,  they  hold  good  in  gen- 
eral, and  in  a  consideration  of  this  subject  the  pattern- 
maker  may   be  understood    to    be  a  wood -worker,  the 


INTRODUCTION  3 

molder  as  one  that  makes  the  molds,  and  the  founder  as 
the  one  that  has  charge  of  the  furnace  and  the  melting 
of  metals. 

In  the  first  of  these  operations,  that  of  the  pattern- 
maker, there  is  needed  a  fine  degree  of  skill  in  the  arts 
of  cabinet  making  and  wood  turning,  Moreover,  the 
two  trades,  the  molder's  and  pattern-maker's,  are  so 
intimately  connected,  that  it  is  almost  impossible  to 
describe  one  without  frequent  reference  to  the  other,  and 
as  a  matter  of  fact  there  is  almost  as  much  to  be  learned 
of  pattern -making  in  the  foundry  as  in  the  pattern  shop. 
So  intimately  connected  are  the  operations  of  pattern - 
making  and  molding,  that  one  of  the  chief  qualifications 
of  a  good  pattern-maker  is  the  ability  to  form  a  rapid  and 
reliable  judgment  as  to  the  best  way  of  molding  a  given 
pattern  out  of  several  ways  possible.  As  there  is  usually 
more  than  one  way  of  molding  a  given  pattern,  it  is 
advisable  that  the  pattern-maker,  if  in  any  doubt,  confer 
with  the  molder  as  to  his  preference  in  the  matter;  as  the 
molder  is  responsible  for  the  production  of  the  casting, 
he  should  have  the  pattern  as  he  wants  it.  As  pattern  - 
making,  therefore,  is  to  be  regarded  primarily  from  the 
molder's  standpoint,  and  not  from  that  of  the  wood- 
worker, the  following  matters  are  of  first  importance: 

(1)  Patterns  being  entirely  enclosed  in  matrices  of 
sand,  provision  must  be  made  for  pulling  them  out;  this 
involves  draught  or  taper,  which  is  a  thinning  down  of 
certain  parts,    division  into  sections,  and  provision  for 
loosening  by  rapping. 

(2)  Molding  sand  is  always  used  damp,  and  pat- 
terns are  subject  to    rough    usage,    consequently  they 
must  be  made  so  as  to  resist  any  tendency  to  change 
their  form  and  size  from  the  absorption  of  moisture  from 


4  WOOD   PATTERN    MAKING 

the  damp  sand,  and  they    must  be  strongly  constructed. 

(3)  Most   metals   shrink  or   contract    in     passing 
from   the  molten   to  the  solid  state;  therefore,   patterns 
must  be  made  larger  than  the  required  casting  to  allow  for 

this. 

(4)  Patterns  may  be  entire  or  complete,  exactly 
like  the  castings  wanted;  however,   if  there  are  cavities 
to  be  formed  in  the  casting,  these  hollow  places  will  be 
represented    by     core     prints.        Moreover,     the     part 
the     pattern-maker     has    to     do    with   getting     out    a 
given  casting  may  be  the  preparation  of  a  sectional  part 
or  parts  of  a  pattern  from  which  only  a  part  of  the  mold 
is  made;  the  other  partis  made  with  a  sweep,  the  boards 
for  which  are  also  prepared  by  the  pattern-maker. 

(5)  The  practice  of  pattern -making  is  largely  gov- 
erned by  the  requirements  of  the  engineer ;  these  require- 
ments are  that  patterns  must  correspond  to  drawings  in 
all  dimensions,  that  all  centers  be  correctly  located,  and 
that  all  necessary  allowances  be  made  both  for  machin- 
ing and  for  the  shrinkage  of  the  metal  of  the  casting. 

It  will  thus  be  seen  that  the  pattern-maker  has  very 
little  in  common  with  carpenters,  or  indeed,  with  any 
other  wood -worker,  except  for  the  fact  that  he  uses  the 
same  tools  and  processes.  To  understand,  then,  the 
fundamental  principles  of  pattern-making,  it  is  necessary 
to  master  the  principles  of  molding,  and  much  of  its 
details  as  well;  and  to  have  a  good  working  knowledge 
of  modern  machine  shop  practice.  It  is  well  to  remember 
also  that  mere  outside  polish  or  finish  on  a  pattern  does 
not  count  for  much  if  such  matters  as  correct  construc- 
tion and  others  already  spoken  of,  are  neglected. 

In  many  trades,  to  become  an  expert  in  handling 
tools,  is  the  most  neceesary  requirement,  but  this  is  not 


INTRODUCTION  5 

the  case  in  pattern -making,  there  being  something  far 
more  important  than  cutting  wood.  In  the  construction 
of  many  patterns  it  is  not  so  much  a  question  of  work- 
manship, as  of  knowledge.  Certain  patterns,  for  example, 
are  very  difficult  to  design,  but  after  they  are  once  made, 
they  can  be  duplicated  by  any  good  wood  -worker.  In  fact, 
it  often  requires  but  little  skill  to  construct  the  necessary 
core  boxes,  etc.,  that  may  be  required  to  produce  certain 
castings.  On  the  other  hand,  there  is  much  pattern - 
making  that  calls  for  fine  workmanship;  in  any  event, 
pattern -making  is  not  merely  cutting  wood. 

From  what  has  been  said,  then,  it  will  readily  be 
appreciated  that  pattern -making  is  an  important  and 
responsible  trade.  For  while  the  duty  belongs  to  the 
draughtsman  of  preparing  the  design,  yet  the  pattern- 
maker must  be  able  so  to  interpret  it  as  to  get  the  idea 
the  draughtsman  intended  to  convey.  Moreover,  he 
must  look  forward  to  the  requirements  of  the  molder; 
consequently,  from  the  drawing  alone  he  must  be  able  to 
imagine  the  completed  casting,  and  build  a  pattern  that 
will  produce  it.  As  the  medium  by  which  the  designer's 
ideas  are  put  into  the  tangible  form  of  a  casting,  his, 
then,  is  a  two-fold  responsibility.  Another  fact  that  adds 
to  his  responsibility  is,  that  there  are  so  many  different 
ways  of  molding.  This  gives  a  great  field  of  study  for 
the  pattern-maker.  The  fact  that  there  are  so  many  dif- 
ferent ways  of  molding  makes  it  advisable  for  the  pattern- 
maker to  consult  the  molder  before  making  patterns  for 
complicated  work. 


CHAPTER  II. 


MOLDING 

A  pattern-maker  should  know  something  about  the 
operations  of  the  molder,  so  that  he  can  make  a  particu-' 
lar  pattern  of  such  a  shape  that  it  can  be  molded  in  the 
easiest  way  possible.  This  baing  the  case,  it  is  necessary 
to  explain  some  of  these  operations.  The  form  of  pattern 
used  in  this  illustration  is  what  is  known  as  a  parted 
pattern ;  the  molding  operations  that  this  form  involves 
are  generally  few  and  simple.  As  will  be  seen  by  Fig.  1, 
the  pattern  is  made  in  two  parts,  the  parting  or  joint  being 
along  the  axis  of  the  cylinder.  It  is  made  in  this  way 


FIG.  1. 

for  the  convenience  of  the  molder.  These  two  parts  are 
held  sideways  in  relation  to  each  other  by  what  are  called 
pattern  pins,  represented  by  dotted  lines,  c  and  d.  Parts 
marked  A  and  B  are  core  prints,  and  will  not  appear  on 
the  casting. 

The  appliance  used  by  the  molder  in  which  to  make 
the  mold  .is  called  a  flask,  and  is  illustrated  by  Fig.  2. 
The  upper  part,  A,  is  called  the  COpe,  the  lower  part,  B, 


MOLDING  7 

the  nowel;  c  is  the  bottom  board,  D,  cope  bars,  E,  guide 

pins.  Each  flask  is  composed  of  at  least  these  three  main 
parts,  viz.,  cope,  nowel,  and  bottom  board.  Sometimes 
another  part  is  introduced  between  the  nowel  and  cope, 
called  the  check,  or  middle  part.  This  is  necessary  when 
the  casting  is  of  such  shape  that  its  pattern  cannot  be 
taken  from  the  mold  with  the  one  parting  obtained  by 
the  use  of  cope  and  nowel  alone,  that  is  with  the  simple 
form  of  flask  shown  by  Fig.  2.  In  addition  to  these 


FIG.  2. 

parts  a  molding  board  is  needed,  which  may  be  just  like 
the  bottom  board.  Only  one  molding  board  is  required 
by  one  workman  for  any  number  of  flasks  of  the  same 
size. 

The  words  top  and  bottom  will  be  frequently  used  in 
writing  of  this  flask.  They  refer  to  the  flask  when 
standing  in  what  may  be  called  its  normal  position,  that 

is,  as  it  stands  when  the  mold  is  ready  for  the  melted 

metal  to  be  poured  in.      The  relative  position  of  these  two 


8  WOOD    PATTERN    MAKING 

parts  is  that  the  cope  is  always  on  top,  the  nowel  at  the 
bottom.  Each  part  is  a  box  having  neither  top  nor  bot- 
tom, the  sides  generally  being  about  5  or  6  inches  high, 
and  rough  inside. 

In  order  that,  after  being  separated,  these  may  be 
put  together  again  in  the  same  relative  position,  they  are 
provided  with  guide  pins  (E)  Fig.  2,  the  pins  proper 
being  on  the  cope,  and  the  lugs  into  which  they  fit,  being 
on  the  nowel.  The  cope  is  also  provided  with  some 
form  of  handles.  In  Fig.  2,  one  of  these  is  shown  at  E, 
being  in  this  case  a  strip  of  wood  about  one  inch  square 
nailed  across  the  end,  directly  above  the  guide  pins. 
These  handles  are  provided  for  the  purpose  of  lifting  the 
cope  from  the  nowel  at  any  time  it  becomes  necessary  to 
do  so  during  the  process  of  molding. 

There  are  also  cross  bars  fastened  across  the  cope 
(D  Fig.  2)  to  assist  in  retaining  the  sand,  which  is  held 
in  place  by  friction  only,  the  cope  from  necessity  having 
no  bottom.  In  all  other  respects  cope  and  nowel  are 
alike,  except  that  in  some  cases  one  may  be  deeper  than 
the  other. 

In  using  this  appliance  the  molder  first  places  the 
molding  board  on  the  sand  floor  of  the  foundry  in  an 
approximately  level  position,  and  so  it  will  not  rock. 
He  then  places  the  half  of  the  pattern  that  is  without 
pins  on  its  flat  side  in  the  center  of  the  molding  board. 
The  nowel,  or  drag,  which  is  the  lower  half  of  the 
flask,  is  next  placed  on  this  board,  bottom  side  up,  with 
the  half  pattern  in  the  middle  of  it.  Next  he  sifts 
molding  sand  on  to  this  board  until  the  half  pattern  is 
covered  to  a  depth  of  an  inch  or  more ;  he  now  shovels 
in  sand  until  the  nowel  is  filled  and  heaped  up;  then, 
with  an  implement  called  a  rammer,  he  rams  it  down 


MOLDING  9 

solid.  The  sand  is  now  struck  off  even  with  the  bottom 
of  the  nowel,  some  loose  sand  thrown  on,  and  the  bottom 
board  placed  on  and  rubbed  around  so  as  to  make  a  solid 
bed  for  the  body  of  sand  in  the  nowel.  Clamps  are  now 
put  on  so  as  to  hold  all  together,  the  whole  is  turned 
over,  the  clamps  removed,  and  the  molding  board  lifted 
off.  This  completes  one  half  of  the  mold,  or,  as  the 
molder  expresses  it,  "the  nowel  has  been  rammed  up 
and  turned  over."  He  now  sleeks  the  surface  with  his 
trowel  until  it  is  even  with  the  flat  surface  of  the  half 
pattern,  which  is  thus  exposed  to  view,  surrounded  by 
sand.  He  now  scatters  on  some  parting  sand,  which  is 
a  very  dry  sand,  usually  burnt  sand  that  has  been  cleaned 
from  castings  already  made.  The  purpose  of  this  is  to 
prevent  the  next  body  of  sand  from  sticking.  The  other 
half  of  the  pattern  is  now  laid  on,  its  position  being 
determined  by  the  pins  already  spoken  of,  and  the  cor- 
responding holes  in  the  other  half  of  the  pattern.  The 
sprue  pin  or  stick  is  now  set  up  on  the  sand  or  parting 
just  finished.  This  pin  is  a  piece  of  wood,  whose  shape 
is  the  frustrum  of  a  cone  about  ten  inches  long;  its  pur- 
pose is  to  make  a  hole  through  the  cope  sand  into  which 
the  melted  metal  may  be  poured.  Sand  is  put  into  the 
cope  in  the  same  way  as  was  done  with  the  nowel ; 
struck  off  even  with  the  top,  the  sprue  pin  pulled  out, 
and  the  whole  surface  brushed  over  so  as  to  remove  all 
loose  sand.  The  cope  is  lifted  off  carefully,  and  set  to 
one  side.  Both  halves  of  the  mold  now  appear  exactly 
alike,  except  that  the  cope  has  the  sprue  hole  running 
through  it. 

The  two  halves  of  the"  pattern  must  now  be  drawn 
or  pulled  out.  This  the  molder  proceeds  to  do  in  the 
following  manner:  If  the  pattern  is  provided  with  lift- 


10  WOOD    PATTERN    MAKING 

ing  plates,  as  all  standard  patterns  should  be,  he  intro- 
duces the  end  of  the  lifting  screw  into  the  hole  provided 
for  it  in  the  lifting  plate,  and  turns  it  in  so  that  it  is  solid. 
If  there  are  no  lifting  plates,  he  drives  what  he  calls  a 
draw  spike  into  one  of  the  halves.  Then,  with  a  mallet, 
a  small  hammer,  or  perhaps  a  sprue  pin,  he  raps  on  all 
sides  of  the  lifting  screw  or  draw  spike,  so  as  to  loosen 
the  pattern.  This  operation,  called  rapping  the  pattern, 
enlarges  the  mold  so  that  the  pattern  may  be  pulled  or 
drawn  out.  This  he  now  does,  very  slowly  and  care- 
fully, gently  rapping  the  pattern  until  it  is  entirely  free 
from  the  mold.  This  is  done  to  both  halves.  A  channel 
is  now  cut  in  the  sand  of  the  nowel  from  the  spot  on  the 
parting  where  the  sprue  pin  was  set,  to  the  mold  or 
cavity  left  by  removing  the  pattern.  Thus  is  provided 
a  passage  through  which  the  melted  metal  may  run  and 
fill  the  mold.  This  channel  is  called  the  gate.  The 
mold  is  now  ready  to  have  the  core  set  in.  After  the 
core  is  set,  the  cope  is  put  back  into  its  original  or  nor- 
mal position,  which  is  determined  by  the  guide  pins; 
the  whole  is  then  clamped  together,  and  set  in  position 
for  pouring.  As  stated  at  the  beginning,  this  process 
applies  only  to  parted  patterns.  This  same  flask  may  be 
used  in  several  different  ways,  the  particular  way  being 
determined  by  the  Shape  and  Size  of  the  pattern.  For 
some  shapes  of  patterns  it  is  necessary  to  use  three 
(3)  boxes  or  partS;  this  is  usually  called  a  three-part  flask, 
thereby  meaning  that  the  mold  is  composed  of  three  dis- 
tinct bodies  of  sand.  The  central  part  of  a  three-part 
flask  is  called  the  cheek.  The  cheek  has  on  it  a  set  of 
guide  pins  the  same  as  the  cope,  and  also  a  set  of  lugs 
like  those  on  the  nowel,  on  the  opposite  edge.  It  is  made 
in  this  way,  so  that  any  cope  or  nowel  of  the  same  size 
may  be  used  with  it. 


MOLDING  11 

These  simple  explanations  will  be  enough  to  give 
the  student  of  pattern -making  a  general  idea  as  to  the  use 
of  patterns  in  the  foundry.  Of  course  there  are  many 
details  to  be  observed  and  carried  out  in  the  production 
of  castings  that  are  not  mentioned  above,  but  as  these 
more  particularly  concern  the  molder  than  the  pattern- 
maker, they  will  not  be  noticed  here. 


CHAPTER  HI. 


GENERAL    PRINCIPLES 

In  building  foundry  patterns  several  ideas  must  be 
be  kept  in  mind,  either  consciously  or  unconsciously. 
These  are  four  in  number,  or  (.when  we  have  no  source 
of  information  as  to  what  is  wanted,  except  a  drawing  of 
the  required  casting),  there  may  be  five,  as  follows: 

(1)  What  may  be  called  the  designer's  idea;  (2)  the 
way  in  which  the  pattern  is  to  be  pulled  from  the  sand ; 
(3)  the  draft,  or  taper,  which  is  a  thinning  down  of  cer- 
tain parts  of  the  pattern  in  order  to  facilitate  its  removal 
from  the  mold  or  sand;  (4)  the  shrinkage  of  the  metal  of 
the  proposed  casting,  while  passing  from  the  molten  to 
the  solid  state;  and  (5)  the  machining  or  finishing  of  the 
casting  after  it  is  made  or  cast. 

An  experienced  pattern -maker  may  not  be  conscious 
that  he  has  in  mind  any  one  of  these  ideas,  because  he 
uses  them  so  frequently  that  he  does  so  without  thinking 
especially  of  them;  in  other  words,  they  become  second 
nature  to  him.  It  is  these  last  four  ideas,  among  others, 
that  separates  this  trade  from  all  other  wood -working 
trades  and  connect  it  with  the  engineering  profession,  for 
there  is  not  one  of  them  that  has  even  to  be  thought  of  by 
those  working  at  any  other  of  the  wood-working  trades. 
Before  we  explain  these  ideas  in  detail,  it  will  be  best  to 
have  them  arranged  before  the  mind  in  such  a  wav  that 


GENERAL   PRINCIPLES  13 

they  may  be  easily  remembered ,  and  in  the  order  of  their 
use  and  importance.  For  convenience,  then,  we  will  put 
them  in  a  vertical  column,  thus: 

1.  Designer's  idea. 

2.  Way  to  be  drawn  from  mold. 

3.  Draft. 

4.  Shrinkage  of  metal. 

5.  Machining. 

Besides  these  five  ideas,  the  last  three  of  which  may 
be  called  allowances,  there  are  two  other  allowances  that 
sometimes  have  to  be  considered,  viz. :  for  shake  and  for 

warp. 

The  two  first  of  these  five  are  purely  abstract  ideas. 
If  it  is  desired  to  make  a  pattern  from  a  drawing  only, 
that  is,  if  there  is  no  other  means  of  knowing  what  is 
wanted,  then  it  will  be  necessary  for  the  one  building  it 
to  form  as  nearly  as  possible  the  same  mental  picture 
that  the  designer  had  in  mind  when  making  the  drawing. 
This  may  be  called  the  designer's  idea,  ind  to  some 
extent,  at  least,  must  be  realized  before  much  can  be 
done  towards  building  a  pattern.  After  having  thus 
formed  in  mind  the  general  shape  and  approximate  size 
of  the  required  pattern,  it  can  be  decided  in  which  way 
it  shall  be  drawn  from  the  mold.  This  must  be  decided 
before  very  much  can  be  done  towards  building  the  pat- 
tern, so  that  the  draft  may  be  made  in  the  right  direc- 
tion, which  is  a  very  important  matter. 

The  other  three  points  that  were  mentioned  are 
sometimes  spoken  of  as  the  allowances  to  be  made  in 
pattern -making.  They  are  really  additions  made  to  the 
size  of  the  pattern  in  some  one  direction,  or,  as  in  the 
case  of  shrinkage,  in  all  directions.  The  first  of  these, 
and  in  some  respects  the  most  important,  is  what 


14  WOOD   PATTERN    MAKING 

is  technically  called  draft.  This  is  a  thinning  down 
of  certain  parts  of  the  pattern;  that  is,  the  vertical  sides 
of  the  pattern  are  tapered,  and  it  is  sometimes  spoken  of 

as  the  taper. 

The  amount  of  draft  to  be  allowed  is  governed  by 
the  case  in  hand,  some  patterns  requiring  more  than 
others.  The  usual  amount  is  1-8  inch  for  1  ft.  in 
height;  this  is  generally  enough  for  small  and  compara- 
tively plain  work,  but  for  complicated  work  it  is  not 
enough.'  No  hard  and  fast  rule,  however,  can  be  given 
for  this  allowance,  or  indeed  for  any  work  in  pattern  - 
making.  What  is  nearest  to  a  general  rule  may  be 


FIG.  3. 
stated  thus :      Give  the  pattern  as   much  draft  up  to  1-4 

inch  per  foot  in  height  as  win  not  interfere  with  the  design. 

Whatever  amount  is  allowed  should  be  added  to  the 
size  of  the  casting  as  given  in  the  drawing.  For  small 
and  plain  work  one -sixteenth  of  an  inch  will  be  enough, 
but  if  the  pattern  is  at  all  complicated,  one -quarter  of  an 
inch  will  not  be  too  much.  Of  course,  the  requirements 
of  the  molder  have  to  be  considered,  and  if  he  was  asked 
about  it  he  would  always  say,  give  it  the  larger  amount.  To 
make  this  more  plain,  we  will  suppose  that  a  pattern  was 
wanted  from  which  to  make  a  mold  for  the  casting  rep- 
resented by  Fig.  3. 


GENERAL   PRINCIPLES  15 

Now  applying  the  above  principle,  we  should  make 
the  top  longer  and  wider  by  }i  inch  than  the  size  given, 
so  that  the  top  of  the  pattern  would  be  8X  inches  long 
and  6J4  inches  wide.  This  addition,  or  allowance  is 
shown  by  the  dotted  lines.  In  this  case  the  pattern 
would  be  drawn  out  of  the  mold  in  the  direction  of  the 
arrow.  In  practice  it  would  not  be  necessary  to  allow 
so  much  draft  on  as  plain  a  pattern  as  this,  but  we  use  it 
as  an  illustration  of  what  is  meant  by  the  term  draft. 
AH  vertical  sides  of  the  pattern,  whatever  its  shape,  HlUSt 
have  SOme  taper  in  order  that  the  molder  may  get  it  out  of 
the  mold  without  breaking  the  mold.  If  no  draft  is 
allowed,  the  molder  has  to  rap  the  pattern  so  much  that 
the  mold  will  be  distorted  and  the  casting  will  not  be 
like  the  pattern. 

The  next  important  principle  to  be  observed,  especi- 
ally when  the  casting  is  required  to  be  exact  in  size,  is 
that  relating  to  shrinkage.  Whenever  this  word  is  used 
in  connection  with  pattern  making,  it  always  means  the 
shrinkage  or  contraction  of  the  metal  of  which  the  cast- 
ing is  made.  An  iron,  brass,  or  steel  casting  is  always 
smaller  than  the  mold  in  which  it  was  made,  and  this  is 
true  also  of  castings  made  of  any  of  the  other  metals  in 
common  use.  This  is  due  to  the  shrinkage  of  the  metal 
when  cooling.  The  amount  of  the  shrinkage  varies  in 
the  different  metals,  and  also  in  the  same  metal  under 
varying  conditions.  Brass  will  shrink  more  than  iron, 
and  iron  that  is  very  hot  when  it  is  poured  into  the  mold, 
will  shrink  more  than  iron  that  is  comparatively  cool 
when  poured.  The  size  and  the  shape  of  the  casting  also 
have  much  to  do  with  the  amount  of  shrinkage.  An 
iron  that  will  shrink  one -eighth  of  an  inch  to  the  foot  in 
light  work,  will  shrink  only  one-tenth  of  an  inch,  or  less, 


16  WOOD   PATTERN    MAKING 

in  large  work.  For  instance,  in  casting  large  box  or 
cylindrical -shaped  castings,  one-tenth  of  an  inch  per 
foot  is  usually  enough  to  allow  for  this  shrinkage  in  the 
diameter,  but  one-eighth  of  an  inch  will  not  be  too  much 
in  the  length.  The  reason  for  this  difference  is  due  to 
the  fact  that  the  castings  are  practically  unrestrained  in 
their  length,  and  are  comparatively  free  to  shrink  in  this 
direction,  while  in  the  diameter  they  are  restricted  by 
the  cores  and  internal  parts  of  the  mold.  The  amount 
of  allowance  usually  made  in  common  practice  is  1-8  Inch 
per  foot,  measured  in  all  directions.  But  since  the 
coefficient  of  shrinkage  is  different  for  different  metals, 
this  is  only  approximate.  The  following  allowances  for 
the  different  metals  are  made  in  the  pattern  when  it  is 
surely  known  just  what  metal  the  casting  is  to  be  made 
of,  as,  of  course,  is  the  case  usually.  One  good  way  to 
remember  these  is  to  arrange  the  figures  that  represent 
these  amounts  in  a  group  like  Fig.  4. 


4. 


For  iron,  then,  this  allowance  is  %„  inch;  for 
brass,  a/is  inch;  aluminum,  Y±  inch,  and  for  steel,  Y\ 
inch;  the  general  amount,  which  is  in  the  center  of  the 
group,  is  %  inch.  It  must  not  be  understood  by  this 
that  these  metals  will  always,  and  under  all  conditions, 


GENERAL   PRINCIPLES  17 

shrink  just  these  amounts;  for,  as  has  already  been  men- 
tioned in  the  case  of  iron,  the  amount  of  shrinkage  varies 
somewhat  under  varying  conditions.  For  the  use  of 
pattern-makers,  scales  or  rules  are  made.  The  one 
most  commonly  used  provides  for  an  allowance  of  ft 
inch  per  foot;  that  is,  the  rule  is  made  ft  inch  longer 
than  the  standard  foot  rule,  and  each  "inch"  is  cor- 
respondingly longer  on  it  than  the  standard  inch.  Scales 
or  rules  can  be  bought  at  dealers,  graduated  for  the  other 
shrinkages  above  spoken  of. 

It  has  been  a  mooted  question  as  to  just  when  this 
shrinkage  or  contraction  takes  place  in  the  casting,  but 
it  is  generally  conceded  now  that  it  takes  place  in  passing 
from  the  plastic  condition  to  the  solid  state.  All  metals, 
i  in  passing  from  the  liquid  to  the  solid  state,  surfer 
expansion  when  in  the  plastic  condition.  It  is  this 
feature  in  the  transition  that  enables  metals  to  take  and 
retain  the  impressions  of  the  molds  with  such  fidelity. 
Allowance  for  shrinkage  is  not  regarded  on  patterns  that 
are  six  inches  or  less  in  area,  as  the  rapping  of  the  pattern 
will  usually  make  up  for  any  shrinkage  that  may  take 
place.  Patterns  that  are  four  inches  or  less  in  size,  are 
made  slightly  smaller  than  the  desired  size  of  the  cast- 
ing. This  is  called  an  allowance  for  shake.  It  is  not 
regarded  unless  it  is  necessary  that  the  casting  be  exact 
m  size.  Patterns  between  six  and  four  inches  may  be 
made  without  regarding  either  shrink  or  shake. 

In  building  machinery  it  is  often  necessary  to  fit  two 
castings  together.  Wherever  this  is  done,  the  two  sur- 
faces that  come  into  direct  contact  are  usually  machined 
in  some  way  in  order  to  obtain  a  smooth,  clean  surface 
of  metal.  A  part  of  a  pattern  that  represents  a  surface 
tf  this  kind  on  the  casting,  must  be  made  larger.  This  is 


18  WOOD   PATTERN   MAKING 

the  case,  whether  the  two  surfaces  are  to  slide  or  rotate 
on  each  other,  or  whether  one  is  simply  bolted  to  the 
other.  It  is  called  an  allowance  for  machining  or  finish,  The 
amount  of  this  allowance  is  generally  ^8  inch,  measured 
perpendicular  to  the  surface  to  be  machined  or  finished. 
If  the  surface  is  simply  to  be  machined  to  fit  another  sur- 
face, and  the  work  is  comparatively  small,  this  will  be 
enough.  But  if  it  is  required  to  have  a  very  nice  finish, 
free  from  all  sand  holes,  or  if  the  work  is  large,  it  might 
not  be  enough;  in  some  cases  it  might  be  necessary  to 
make  it  twice  the  amount,  or  %  inch  on  each  surface. 
Moreover,  as  the  casting  increases  in  size,  its  irregulari- 
ties also  increase,  so  that  a  larger  amount  must  be 
allowed.  In  the  case  of  large  work,  such  as  engine  beds, 
the  allowance  is  frequently  made  from  %  to  1  inch.  A 
large  allowance  is  especially  necessary  on  very  irregular 
and  new  work,  as  the  amount  of  distortion  caused  by  the 
strains  setup  in  the  casting  by  shrinkage  is  very  uncertain. 
L,arge  steel  castings  are  usually  very  rough,  and  also 
become  more  or  less  distorted  in  cooling  and  anneal- 
ing, so  that  it  is  necessary  to  allow  more  on  this  account. 
Of  course,  the  exact  amount  must  be  determined  by  the 
circumstances  of  any  given  casting,  but  there  should  be 
enough  so  that  in  taking  the  first  cut,  the  tool  used  may 
get  beneath  the  sandy  scale  that  is  always  present  on  a 
casting,  and  still  leave  enough  for  a  second  cut  at  least, 
and  a  third  or  finishing  cut  if  necessary.  It,  therefore, 
cannot  be  much  less  than  one-eighth  of  an  inch. 

There  is  one  other  allowance  to  be  mentioned  that  is 
not  usually  called  for  in  making  machinery  patterns,  but 
is  frequently  in  making  what  are  called  architectural 
patterns.  Some  castings,  because  of  their  varying  thickj 
ness,  or  because  of  one  surface  being  more  exposed  than 


GENERAL   PRINCIPLES  19 

another,  therefore  cool  more  rapidly,  warp  or  become 
distorted  in  the  mold  when  cooling.  To  overcome  this, 
patterns  for  castings  of  shapes  that  are  known  thus  to 
warp,  are  made  of  such  a  shape  that  in  cooling  they  will 
assume  the  desired  shape.  This  change  in  shape  of 
patterns  is  called  an  allowance  for  "warp." 


CHAPTER  IV. 


MATERIALS 


Wood  is  the  material  used  for  a  large  majority  of 
patterns.  At  first  thought  it  would  seem  that  wood  is 
a  particularly  unsuitable  material  to  be  used  in  matrices 
of  damp  sand,  and  to  be  subject  to  such  rough  usage  as 
the  ramming  and  rapping  of  a  pattern  necessarily 
involves,  but  there  are  several  reasons  why  wood  is  used. 
The  first  that  may  be  mentioned  is  that  it  is  easily  worked 
and  altered.  Secondly,  it  is  light  and  portable.  Further- 
more, by  exercising  due  care  in  construction,  its  dis- 
advantages may  in  a  degree  be  overcome.  The  pattern- 
maker, of  course,  meets  with  the  same  difficulties  with 
which  other  wood -workers  have  to  contend,  and  as  inter- 
fere with  the  durability  of  patterns.  The  chief  one 
among  these  is  due  to  the  tendency  of  wood  to  shrink 
and  swell,  which  cause  warping  and  change  in  form  and 
size.  This  cannot  be  wholly  overcome,  but  by  arranging 
the  different  pieces  in  a  given  pattern  with  a  due  regard 
for  this  natural  tendency,  it  may  to  a  degree  be  counter- 
acted. To  prevent  warping  it  is  necessary  to  know  the 
effect  this  tendency  has  upon  the  individual  board ;  and 
this  may  be  determined,  if  the  position  of  the  board  in 
the  log  is  known,  which  may  be  determined  by  examin- 
ing the  end.  If  a  board  is  cut  from  the  middle  of,  and 
directly  through  the  diameter  of  the  log,  it  is  not  very 


MATERIALS  21 

likely  to  warp;  but  if  a  board  is  cut  from  a  position  mid- 
way between  the  heart  and  the  outside  of  the  log,  it  is 
sure  to  do  so,  for  it  will  assume  a  curved  outline  between 
the  edges,  the  heart  side  always  becoming  convex.  This 
is  caused  by  the  more  rapid  drying  of  the  board  on  the 
sap  side.  For  as  the  board  is  cut  through  the  concentric 
cylindrical  layers  of  which  the  log  is  composed,  the 
outer  side  of  the  board  contains  more  exposed  fibre  ends 
and  more  open  pores  than  the  heart  side.  Consequently, 
the  sap  side  of  a  board  gives  off  the  moisture  it  contains 
more  rapidly,  and  it  will  also  absorb  moisture  more 
rapidly.  In  view  of  this  fact,  the  sap  side  of  any  board 
should  be  placed  where  it  will  be  the  least  likely  to  be 
exposed  to  any  change  in  atmospheric  conditions.  That 
is,  whenever  it  is  possible,  this  side  of  the  board  should 
be  always  placed  on  the  inside  of  any  pattern  work. 

What  is  known  as  quarter-sawn  lumber  is  the 
best  for  pattern -work  and  all  wood-work,  because  it  is 
not  so  likely  to  warp  as  is  the  regular,  or  bastard-sawn. 
Quarter- sawn  lumber  is  lumber  that  is  sawn  approxi- 
mately parallel  with  the  medullary  ray.  The  trunk  of  a 
tree  is  made  up  of  concentric  cylindrical  layers,  bound 
together  with  radial  fibres,  which  are  known  as  medul- 
lary rays.  It  is  the  exposure  of  these  rays  that  gives  to 
quartered  oak  the  beauty  that  is  so  much  prized.  How- 
ever, quartering  is  a  very  wasteful  way  of  sawing  lumber, 
and  involves  an  extra  cost.  But  for  pattern  work  that 
must  be  made  thin,  it  pays  to  use  quarter-sawn  lumber, 
even  if  it  does  cost  more. 

Another  very  important  factor  in  connection  with 
lumber  for  patterns  is,  that  it  should  be  thoroughly 
seasoned  before  being  used,  if  possible,  by  what  is  known 
as  the  natural  or  air  seasoning  process.  The  seasoning 


22  WOOD   PATTERN    MAKING 

should  continue  for  at  least  tWO  years,  in  order  that  the 
natural  gums  of  the  wood  may  be  fixed;  that  the  rapid 
drying  of  the  kiln  will  not  drive  them  out  and  in  that 
way  make  the  wood  more  porous.  Lumber  intended  for 
pattern  work,  if  allowed  to  remain  in  a  shed  with  a 
waterproof  roof  for  two  years,  will  give  better  results 
than  lumber  exposed  to  all  sorts  of  weather  for  six 
months,  and  then  placed  in  a  dry  kiln  to  finish  the  pro- 
cess. For  one-inch  lumber  two  years  is  enough;  thick- 
er planks  will,  of  course,  need  more  time,  say  four 
years  for  two -inch.  However,  lumber  cannot  be  so 
thoroughly  seasoned  as  to  give  entire  permanence  of 
form  and  durability  to  patterns  made  from  it. 

Besides    being    thoroughly    seasoned,    lumber    for 

patterns     should    be    straight,     and     even    in    grain, 

not  too  hard  to  be  easily  worked,  yet  not  so  soft 
as  to  be  unduly  injured  by  the  rough  usage 
patterns  must  necessarily  undergo  in  the  foundry. 
There  is  no  wood  that  fulfills  these  conditions  better 
than  what  is  known  as  White  Pine  (Pinus  Strobus), 
sometimes  called  "cork  pine"  because  of  the  cork -like 
appearance  of  the  bark.  This  wood,  when  thoroughly 
seasoned,  will  retain  its  shape  very  admirably  under  the 
excessive  atmospheric  changes  that  patterns  have  to 
undergo  from  pattern-shop  to  foundry,  and  from  foun- 
dry to  the  storage  loft.  When  first  cost  need  not  be 
considered,  and  it  should  not  be  in  the  case  of  small 
standard  patterns,  Mahogany,  what  is  known  in  the 
market  as  Honduras  M.,  is  the  best  wood  for  all  patterns; 
it  is  very  even  and  straight  in  the  grain,  not  so  hard  but 
that  it  can  be  easily  worked,  and  retains  its  form  and 
size  to  a  remarkable  degree.  One  thing  to  be  men- 
tioned in  this  connection  is  the  arranging  or 


MATERIALS  23 

combining  the  several  pieces  of  which  a  pattern  is  made  in 
such  a  way  that  any  shrinking  or  swelling  of  the  wood 
shall  not  change  the  shape  or  size  of  the  pattern.  This 
is  an  important  matter  in  some  classes  of  work,  and 
should  have  the  careful  consideration  of  the  pattern- 
maker, especially  in  the  case  of  standard  patterns.  If 
this  is  done  it  will  add  considerably  to  the  durability  of 
a  pattern. 

There  is  one  principle  it  is  well  to  observe  in  combin- 
ing the  several  pieces  of  wood  in  a  pattern,  and  that  is 
to  have  as  near  as  possible  the  grain  of  the  wood  run  in 
the  same  general  direction,  so  that  as  it  shrinks  or 
swells  it  will  do  so  in  the  same  direction,  and  there- 
fore will  not  distort  the  pattern. 

Special  patterns  are  often  made  of  brass,  iron,  white 
metal  or  aluminum.  These  metals  would  be  used  in  light 
or  curved  work,  and  also  when  a  large  number  of  cast- 
ings of  the  same  size  and  shape  are  wanted.  With  few 
exceptions,  however,  original  patterns  are  made  of  wood. 
Statuary  and  other  ornamental  work  is  usually  modeled 
in  wax  or  clay,  which  serves  as  the  pattern.  When  it  is 
proposed  to  use  a  metal  pattern  for  the  production  of 
castings,  the  original  pattern  is  made  of  wood  and  is  called 
a  master  pattern  or  double -Shrinkage  pattern.  This  is 
made  with  a  double -Shrinkage  allowance,  so  that  a  casting 
made  from  it  will  still  be  large  enough  for  the  pattern 
from  which  to  make  the  castings  wanted.  Patterns  made 
of  wood  must  be  varnished  or  they  will  soon  go  to  pieces. 

SANDPAPER 

In  pattern  work  sandpaper  should  be  used  with  dis- 
cretion. The  pattern  should  be  formed  as  nearly  to  shape 
and  size  and  finished  as  accurately  as  possible  with  th 


24  WOOD    PATTERN    MAKING 

cutting  tools  before  sandpaper  is  used.  Under  no  cir- 
cumstances should  sandpaper  be  used  for  cutting  down 
or  removing  any  considerable  amount  of  stock,  or  for 
doing  anything  that  can  be  done  with  tools.  Otherwise 
the  draft  and  the  accuracy  may  be  impaired.  Sandpaper, 
as  its  name  implies,  is  made  of  sharp  sand  (Quartz  or 
Garnet)  glued  on  paper.  It  is  graded  according  to  the 
grains  of  sand,  and  numbered  accordingly.  The  grades 
most  useful  to  the  pattern-maker  are  Nos.  0-2.  No.  l£ 
is  best  for  use  directly  on  the  wood,  and  No.  1  for  the 
varnished  surface.  Ordinarily,  sandpaper  should  be 
rubbed  across  the  grain  of  the  wood.  In  the  last  two  or 
three  years,  what  are  called  pattern -grinding  or  sanding 
machines  have  been  introduced  to  the  trade  to  take  the 
place,  in  some  kinds  of  work,  of  sandpapering  by  hand, 
and  they  accomplish  the  work  much  better  and  more 
rapidly.  Any  kind  of  abrasive  that  can  be  fastened  to 
the  machine  may  be  used. 

GLUE 

In  pattern -making  as  in  most  of  the  wood -working 
trades,  glue  is  depended  on  for  adhesive  fastening.  For 
fastening  leather  fillets,  shellac  varnish  is  sometimes 
used.  Since  much  depends  on  the  character  of  the  glue 
used,  it  should  be  of  the  best.  There  are  many  kinds 
and  qualities  of  glue  on  the  market,  including  liquid, 
pulverized  or  ground,  and  sheet.  The  liquid  glue  is 
always  ready  for  use  and  is  very  good  for  small  work. 
The  sheet  or  flake  form,  ground,  dissolved  and  applied 
hot  is  the  best  for  general  use.  Animal  glue  comes  in 
thin  sheets;  it  is  the  best,  and  likewise  the  most  expen- 
sive. Of  late  years  the  large  manufacturers  of  glue  have 
taken  up  the  practice  of  grinding  these  sheets,  which 


MATERIALS  25 

makes  it  much  handier  for  use.       However,  this  enables 
dishonest  dealers  to  grind  the  cheaper  kinds  of  glue  and 
pass  them  off  as  the  best,  for  when  ground  it  requires  an 
expert  to  tell   the  difference,   but  when  it  is  cooked,  the 
odor  given  off  will  generally   indicate  its   quality.     As  a 
rule,  the  best  quality  of  glue  is  of  an  amber  color,  and 
the  sheets  rather  thin.        Whichever  kind  (excepting  of 
course  the  liquid)  is  used,    it   should    be  soaked  in  cold 
water  for  a  short  time  before  cooking;  only  a  small  quan- 
tity should  be  prepared  unless  the  shop  is  provided  with 
a  steam  glue  heater  that  is    kept   hot.       Glue    is    much 
stronger  if  used    while   fresh,    as    frequent   heating  and 
cooling  destroys  its  strength.       To    obtain  the  best  and 
strongest  joint,  the  wood  should  be  slightly  warmed  too 
say  from  90  to  120  degrees,  and  the  glue  applied  as  hot 
as  possible,  and  the  work  quickly  clamped.      As  a  rule, 
the  harder  the  glue    the   better   it   will    resist  moisture.' 
When  it  is  necessary  to  glue  two  pieces  of  wood  together 
so  that  the  joint  is  on  the  end  grain,  the  end  should  first 
be  given  a  coat  of  thin  glue,  which  should  be  allowed  to 
dry  before  applying  the  glue  for  the  joint.  This  is  called 
SIZIRg  the  joint.     Plenty  of  time  should  be  given  the  joint 
to  dry-ten  to  twelve  hours,  according  to  the  size  of  the 
work,  will  usually  be  enough  if  in  a  warm  and  dry  shop 
or  room.     To  much  care  cannot  be  exercised  in  the  use 
of  glue  for  pattern  work,  indeed  it  is  not  advisable  to  use 
it  at  all  when  nails  or  screws  will  answer   the   purpose. 
But  there  are  some  kinds  of  patterns  that  cannot  be  made 
without  it.    ' 

VARNISH 

All  wooden  patterns  should  be  covered  with  some 
kind  of  protective  coating  so  as  to  prevent  as  much  as 
possible  the  absorption  of  moisture  from  the  damp  sand 


26  WOOD    PATTERN    MAKING 

of  the  mold,  for  this  is  very  injurious  to  all  wood  work. 
The  protective  coating  should  be  of  such  a  nature  as  to 
be  unaffected  by  moisture  and  also  to  insure  a  hard,  Smooth 
Surface  that  will  "draw"  easily  from  the  mold. 

In  practice  there  are  two  general  classes  of  varnishes, 
Shellac  and  Copal.  The  first,  which  is  the  kind  most 
generally  employed,  is  composed  of  common  Gum  Shel- 
lac cut  with  alcohol  and  colored,  if  so  wanted,  with  some 
kind  of  coloring  ingredient.  The  second  comprises  the 
better  grades  of  Copal  varnishes  used  by  finishers.  This 
may  also  be  colored.  By  changing  the  color  of  the  var- 
nish employed,  it  is  possible  to  distinguish  between  core 
prints  and  the  body  of  the  pattern,  and  also  between 
patterns  for  castings  of  different  metals,  such  as  brass, 
iron  and  steel. 

For  shellac  varnish  a  good  grade  of  gum  should  be 
used  as  the  cheaper  grades  will  not  stand  up  to  the 
work.  This  is  usually  called  yellOW  varnish.  Black 
varnish  is  made  by  adding  lampblack ;  a  good  quality  of 
lampblack  should  be  use,  one  that  is  free  from  grit. 
Red  varnish  is  made  by  adding  some  red  powder,  usually 
Indian  red,  or  Vermillion  (Chinese  is  best)  to  the  yellow 
varnish.  The  use  of  these  in  varnish  seems  to  give  it  a 
better  body  and  greater  durability.  Copal  varnish,  how- 
ever, is  still  more  durable,  and  if  time  (about  three  days) 
can  be  given  it  to  dry,  it  is  much  the  better  and  will  out- 
last several  coats  of  shellac  varnish. 
BEESWAX 

Beeswax  is  used  for  making  small  fillets,  and  filling 
small  holes,  such  as  nail  holes,  etc.,  and  any  other  slight 
defect  in  either  material  or  workmanship.  It  may  also 
be  employed  for  making  a  slight  change  in  the  form  of 


MATERIALS  27 

a  pattern  that  is  not  much  used.  It  is  not  good  practice, 
however,  to  use  it  in  this  way  on  standard  patterns,  as 
it  is  very  liable  to  melt  and  run  out  in  the  storage  loft 
during  warm  weather. 

Wax  is  sometimes  used  for  coating  iron  patterns  to 
prevent  them  from  rusting.  To  cover  iron  patterns  with 
wax,  they  should  first  be  made  as  warm  as  they  can  be 
handled,  then  the  wax  should  be  spread  on  them  as 
evenly  as  possible  and  brushed  over  with  a  soft  brush. 

NAII.S 

For  pattern  work,  what  are  known  as  "wire  brads" 
are  the  best  nails.  They  can  be  driven  almost  anywhere 
in  the  wood  without  splitting  it.  They  may  be  had  of 
all  lengths  from  one -half  inch  to  three  inches  and  of 
different  sizes  of  wire.  However,  owing  to  the  necessity 
of  rapping  patterns  when  drawing  them  from  the  mold, 
it  is  always  best  to  use  screws  when  fastening  the  differ- 
ent parts  of  a  pattern  together.  They  are  much  better 
than  nails  on  account  of  the  clamping  effect  they  give  to 
the  pieces  to  be  joined.  This  is  a  very  desirable  effect 
in  the  case  of  standard  patterns.  Another  reason  why 
screws  are  much  better  than  nails  for  this  purpose  is  that 
when  it  is  necessary  to  change  or  repair  a  pattern,  screws 
can  be  taken  out  without  tearing  the  wood  of  the  pattern, 
and  if  needed,  can  be  replaced  exactly  in  the  same  place. 
Screws  are  also  handy  for  temporarily  securing  loose 
parts  of  a  pattern,  and  for  this  use  are  much  superior  to 
nails  or  pins,  When  screws  are  to  be  used  for  fastening 
two  pieces  of  wood  together,  holes  as  near  the  size  of 
shank  of  screw  as  possible  should  be  bored  through  the 
upper  piece.  If  this  is  not  done  the  screw  will  cut  a 
thread  in  both  pieces  thus  hindering  the  clamping  effect 


28  WOOD    PATTERN    MAKING 

that  is  otherwise  obtained  by  the  use  of  screws    for  this 
purpose. 

As  is  well  known  to  most  wood -workers,  end  grain 
wood,  especially  soft  wood,  does  not  hold  a  screw  very 
securely,  unless  some  special  method  is  used.  One  of 
the  best  ways  of  putting  screws  into  end  grain  is  to  bore 
a  hole  of  a  size  as  near  as  can  be  to  the  size  of  the  solid 
part  of  the  screw.  The  thread  of  the  screw  will  then 
cut  its  way  into  the  wood  without  disturbing  the  fiber 
and  thus  the  full  shearing  strength  of  the  wood  will  serve 
to  hold  the  strain  put  upon  the  screw.  The  hold  of  a 
screw  in  end  wood  may  be  increased  by  taking  it  out, 
placing  a  small  amount  of  glue  in  the  hole,  and  putting 
the  screw  back  in  at  once  while  the  glue  is  soft.  It  is 


FIG.  5. 

sometimes  necessary  to  take  out  and  reinsert  screws  in 
end  wood,  repeatedly,— for  instance,  when  pattern  work 
has  to  be  taken  apart  for  convenience  in  molding.  In 
such  cases,  simply  screwing  them  into  the  end  wood 
should  not  be  depended  upon,  as  they  get  loose  and  do 
not  hold.  A  good  way  to  overcome  this  difficulty  is 
illustrated  by  Fig.  5.  It  is  to  bore  a  hole  at  right  angles 
to  the  direction  of  the  screw  in  such  a  position  that  the 
screw  shall  pass  through  it;  fill  this  hole  with  a  hardwood 


MATERIALS     '  29 

plug,  bore  a  hole  of  suitable  size  for  the  screw  and  insert 
the  screw.  If  now  the  screw  from  frequent  taking  out 
and  screwing  in  becomes  loose,  the  plug  may  be  taken 
out  and  another  put  in  its  place.  As  noted  elsewhere, 
screws  make  a  much  stronger  fastening  than  nails  and 
should  always  be  employed  in  pattern  work  that  is  to  be 
much  used,  as  in  the  case  of  a  standard  pattern. 


Clement  Universal  Sander 


CHAPTER  V. 


FILLETS 


Sharp  corners  on  a  casting,  whether  inside  or  out- 
side, generally  detract  greatly  from  its  appearance,  and 
also,  in  the  case  of  internal  angles  especially,  injure  its 
strength.  This  being  the  case,  sharp  corners  must  be 
avoided  in  the  pattern,  as  the  casting  will  be  of  the  same 
shape  as  the  pattern.  The  weakness  due  to  sharp  cor- 
ners, especially  in  the  case  of  internal  angles,  is  caused 
by  the  way  iron  acts  in  cooling,  or  in  passing  from  the 


FIG.  6. 


FIG.  7. 


molten  to  the  solid  state.  There  are  always  more  or  less 
strains  set  up  in  a  casting  by  the  shrinkage  or  contrac  - 
tion  that  takes  place  at  that  time.  As  the  iron  hardens 
the  crystals  seem  to  arrange  themselves  in  such  a  man- 
er  that  their  lines  of  strength  are  perpendicular  to  th4 


FHJ,ETS 


faces  of  the  casting.  For  instance,  in  a  casting  of  the 
general  shape  shown  by  Fig.  6,  these  lines  arrange  them- 
selves as  shown  by  the  short  lines  drawn  perpendicular 
to  each  face  and  thus  leave  the  space  (a)  open  or  honey- 
combed, consequently  the  casting  will  be  very  weak 
through  the  line  (be),  and  when  a  strain  is  put  upon  it, 
it  will  be  likely  to  break.  In  some  shapes  of  castings 
these  strains  caused  by  shrinkage  will  of  themselves 
crack  the  casting  at  this  point  and  at  all  similar  sharp 
internal  angles.  If  the  above  casting  is  made  with  a 
fillet  or  rounded  -in  angle,  this  is  not  so  likely  to  be  the 
case,  and  if  it  is  made  as  represented  by  Fig.  5  it  will  be 
just  as  strong  at  that  point  as  at  any  other.  For,  as  will 
be  noticed,  there  is  no  place  for  this  irregular  crystalli- 
zation to  take  place.  In  view  of  these  well-known  facts, 
all  internal  angles  should  be  thus  rounded  in  or  "filleted" 
on  the  pattern. 


FIG.  7 


There  is  another  advantage  gained  in  thus  rounding 
m  these  internal  angles  that  is  appreciated  by  the  molder. 
In  molding  a  pattern  of  the  general  shape  of  Fig. 7 (a),  that 
for  some  reason  has  to  be  pulled  or  drawn  from  the  mold 
m  the  direction  of  the  arrow,  a  very  sharp  corner  of  sand 


32  WOOD   PATTERN    MAKING 

will  be  left  at  the  point  (c) .  As  the  pattern  is  pulled  up 
by  it,  a  slight  movement  of  the  pattern  sidewise  would 
break  it;  then  as  soon  as  the  pattern  became  clear  of  the 
mold,  the  sand  would  fall  down  into  it,  thus  making 
what  the  molder  would  call  a  dirty  mold.  It  would  cause 
him  some  trouble  to  remove  this  sand  from  the  mold, 
and  it  must  be  all  cleaned  out,  for  otherwise  it  would 
surely  make  a  poor  spot  on  the  casting  and  might  render 
it  unfit  for  the  use  to  which  it  was  intended  to  be  put. 
Therefore,  for  the  molder 's  benefit  as  well  as  to  strengthen 
the  casting,  it  is  best  to  round  in  any  internal  angles. 
Fillets  may  be  made  of  wood,  wax  or  leather.  The  last 
is  undoubtedly  the  best;  it  also  is  the  most  expensive, 
at  least  in  its  first  cost.  Wood  is  generally  used  for 
straight  work,  the  best  practice  being  to  fit  and  glue  a 
piece  of  wood  of  the  right  size  into  the  angle  and  allow 
it  to  dry  before  cutting  the  required  curve.  By  work- 
ing the  curve  after  it  is  glued  in  place,  the  tendency  of 
thin  edges  of  wood  to  curl  when  made  wet,  which  of 
course  is  done  in  the  glueing,  is  entirely  overcome.  There 
is  no  objection  to  using  wood  for  this  purpose  if  the  wood 
that  is  used  is  straight  in  grain,  and  if  the  grain  of  the 
wood  of  which  the  fillet  is  made  lies  in  the  same  direc- 
tion as  the  grain  of  the  wood  composing  the  part  of  the 
pattern  to  which  it  is  glued.  Leather  is  the  best  material 
of  which  to  make  fillets,  since  it  is  elastic  enough  to 
corne  and  go  with  the  wqod  as  it  shrinks  and  swells.  It 
is  as  permanent  as  the  pattern  itself,  gives  a  very  smooth 
finish,  and  is  easily  applied.  Wax  is  not  very  good 
except  for  very  small  fillets  or  for  temporary  patterns. 
It  should  not  be  used  for  fillets  on  standard  pattern 
work  as  it  is  likely  to  melt  and  run  out  when  exposed 
to  summer  heat  in  the  storage  loft. 


FILLETS 


33 


In  making  and  applying  fillets  of  wood,  the  process 
is  something  like  this :  First,  a  piece  of  wood  of  the 
proper  length  is  ripped  out  square,  so  that  each  side  is 
equal  to  the  radius  of  the  curve  of  the  proposed  fillet. 
One  corner  is  fitted  to  the  angle  proposed  to  be  filleted; 
it  is  better  if  this  does  not  exactly  fit  clear  into  the  angle', 
that  is,  the  fillet  piece  may  be  a  little  loose  at  the  apex 
of  the  angle  but  should  fit  tightly  on  the  other  two  sides 
of  the  triangle.  When  this  is  properly  fitted  the  remain- 
ing or  outside  angle  may  be  planed  off  with  the  jack 
plane  so  as  to  make  a  triangular- shaped  piece.  The 
third  side,  the  one  last  made,  is  a  good  place  in  which 
to  drive  brads  for  holding  the  piece  in  place  while  the 
glue  is  drying.  The  brads  should  be  placed  about  four 
inches  apart.  When  a  sufficient  number  of  brads  have 
been  started,  the  glue  may  be  applied  to  the  piece,  the 
piece  set  into  the  angle  and  the  brads  driven  in  as  far  as 


FIG.  6    (a) 

=an  be,  while  still  leaving  the  heads  protruding,  so  that 
:hey  may  be  pulled  out  when  the  glue  is  dry.  When  the 
?lue  is  thoroughly  dry  the  nails  may  be  pulled  out,  and 


34  WOOD   PATTERN   MAKING 

the  required  curve  cut  or  worked  with  gouge  and  sand- 
paper, making  it  as  nearly  tangent  as  possible  to  the 
two  sides  it  connects.  This  work  is  illustrated  by  Fig. 
6  (a).  In  order  to  apply  leather  fillets  successfully,  a 
tool  known  as  a  "filleting  tool"  is  needed.  It  consists 
of  a  sphere  of  iron,  or,  still  better,  of  brass,  fastened  to  a 
short  rod  somewhat  smaller  than  the  sphere.  The 
diameter  of  the  sphere  should  be  equal  to  that  of  the 
fillet.  After  the  leather  fillet  is  cut  to  the  required 
length,  moderately  thick,  clean  glue,  not  too  hot,  is 
applied;  the  leather  is  placed  in  the  angle,  and  the  fillet- 
ing tool  is  run  along  the  angle,  pressing  the  leather 
firmly  into  place.  The  pressing  should  be  done  heavily 
enough  to  squeeze  out  all  surplus  glue,  which  should  be 
cleaned  off  at  OI1CC  with  a  piece  of  cloth  or  waste 
dampened  with  hot  water;  then  the  surface  thus  made 
wet  should  be  wiped  as  dry  as  possible  with  a  dry  piece 
of  the  same  material.  The  filleting  tool  should  be  quite 
warm  for  this  operation. 

Wax  fillets  are  put  in  in  the  following  man- 
ner: Some  wax  is  softened  by  heat  and  rolled  into  a 
omall  cylinder,  the  diameter  of  which  is  governed  by  the 
size  of  the  fillet.  It  is  then  laid  in  the  angle.  The  fillet- 
ing tool  before  mentioned  is  warmed  enough  to  soften 
the  wax,  and  the  cylinder  is  pressed  into  the  angle.  The 
wax,  being  softened,  conforms  to  the  shape  of  the  tool, 
which,  as  it  is  passed  along,  leaves  a  circular  surface 
tangent  to  the  two  sides  of  the  angle  The  surplus  wax 
should  be  cleaned  off  up  to  the  line  made  by  the  tool.  This 
makes  a  very  nice  job,  and  is  a  good  way  of  making 
fillets  for  patterns  that  are  not  to  be  much  used.  There 
are  on  the  market  small  presses  that  turn  out  cylinders 
of  wax  for  making  wax  fillets.  They  are  so  arrange 


FILLETS  35 

that  different  sizes  of  cylinders  are  made  for  different 
sizes  of  fillets.  These  small  cylinders  of  wax  are  also 
used  for  venting  cores  and  molds.  These  machines  save 
considerable  time  and  trouble  in  this  kind  of  work,  and 
also  do  it  more  satisfactorily. 


CHAPTER  VI. 

.     CORES. 

When  castings  with  holes  through  them  or 
with  internal  cavities,  are  to  be  made,  a  pro 
jectmg  body  of]  sand  must  either  be  made  in  the 
mold  at  the  same  time  as  the  rest  of  the  mold,  or  else  be 
introduced  into  the  mold  after  the  pattern  is  removed  or 
pulled  out.  These  projecting  bodies  of  sand  are  called 
cores.  When  the  pattern  can  be  withdrawn  from  the  mold 


FlG-  8.  FIG.  9. 

md  leave  a  core,  or  cores,  as  a  part  of  the  mold,  it  is  said 

0  leave  its  own  core  or  cores.     This  is  illustrated  by  Figs. 

1  and  9.      Fig.    8  represents  a  pattern   that  has  been 
lolded  and  removed  from  the  mold;    (Fig.  9)  leaving 
ore  (a)  projecting  above  the  lower  surface  of  the  mold. 
Vhen  the  cope  is  closed'the' [cope  sand  will,  of  course 

/  &8OS 


38  WOOD   PATTERN    MAKING 

touch  the  upper  surface  of  these  cores ;  when  the  mold  is 
filled  with  melted  metal,  it  cannot  get  where  these  cores 
are.  The  result  is  that  the  casting  will  have  a 
hole  through  it  the  shape  of  the  core  (a).  Where  pat- 
terns cannot  be  so  made  and  molded  with  the  ordinary 
appliances  of  the  foundry  to  form  their  own  cores,  there 
is  added  to  the  pattern  an  attachment  or  projection  that 
forms  a  mold  in  the  sand,  into  which  a  separate  core  may 
be  placed.  These  attachments  are  called  COFC  priltS. 

These  cores  that  are  made  separate  from  the  mold 
are  usually  what  are  called  dry  Sand  cores,  although 
green  Sind  cores  are  sometimes  made  in  the  same  way. 
A  simple  form  of  pattern  for  a  mold  with  a  dry  sand  core, 
is  represented  by  Fig.  1,  parts  A  and  B  being  core 
prints. 

A  dry  sand  core  is  made  in  a  separate  device 
called  a  core  box.  In  the  case  of  a  symmetrical  core,  a 
core  box  is  made  only  for  a  small  portion  of  it.  For  a 
cylindrical  core  only  a  half  box  need  be  made;  two 
cores  from  such  a  box  be  pasted  together,  thus  form- 
ing a  complete  core.  This  same  principle  may  be  used 
in  the  case  of  very  large  work.  A  symmetrical  mold, 
like  one  for  a  fly  wheel,  may  be  built  up  almost  entirely 
with  cores. 

Core  boxes  require  as  great  care  in  their  manufac- 
ture as  patterns,  and  as  much  thought  must  be  given  to 
their  shape,  durability  and  finish.  The  shape  of  a  pattern 
is  nearly  like  the  required  casting;  but  the  inside  of  the 
core  box,  which  is,  of  course,  the  necessary  part,  is  just 
the  reverse,  resembling  more  nearly  the  shape  of  the 
mold.  When  cores  are  made  in  boxes  and  inserted  in 
the  mold,  it  is  necessary  that  they  be  supported  insuch'a 
way  that  there  will  be  no  chance  for  a  change  of  position 


CORES  39 

during  the  time  the  mold  is  being  filled  with  the  molten 
metal.  To  give  this  support,  special  recesses  are  made 
in  the  mold  to  receive  them.  These  recesses  are  made  by 
the  core  prints  previously  mentioned.  The  core  should 
exactly  fill  the  recesses  left  by  the  core  prints,  and  this 
part  of  the  core  should  be  large  enough  to  support  the 
core  properly  in  place,  so  that  the  sand  of  the  mold  will 
not  be  crushed  out  of  shape  by  the  weight  of  the  core, 
nor  by  the  action  of  the  metal  while  being  poured  into 
the  mold. 

Core  prints  should  be  given  more  taper  than  the 
pattern  itself,  so  that  the  work  of  withdrawing  the  pattern 
from  the  mold  may  not  be  unduly  increased  by 
their  presence,  and  also  so  that  the  core  may  be  the 
more  easily  adjusted  to  its  proper  position.  In  the  case 
of  plain  cylindrical  cores,  whose  length  does  not  exceed 


FIG.  10. 

five  times  their  diameter,  or  of  such  as  may  be  stood  on 
end  while  drying,  a  full  box  may  be  constructed  and  the 
cores  made  whole.  This,  of  course,  saves  the  time  of 
the  core -maker,  as  he  does  not  have  to  cement  the  two 
halves  together.  A  core  made  in  this  way,  with  its  box, 
or  mold,  is  represented  by  Fig.  10.  In  making  these 
core  boxes  and  core  prints,  care  should  be  taken  that  the 


40  WOOD   PATTERN    MAKING 

part  of  the  box  corresponding  to  the  print  on  the  pattern 
should  be  exactly  the  same  size  and  shape  as  that  print,  so 
that  when  the  core  is  set  into  the  mold  it  shall  exactly  fit. 

All  core  prints  should  be  of  ample  size,  so  that  their 
impression  will  hold  the  cores  in  their  place,  and  so 
that  the  weight  of  the  core  and  the  weight  and  action  of 
the  melted  metal  will  not  change  the  position  of  them. 
It  is  well  to  remember  that  the  material  that  must  do 
this  holding  is  only  loam,  or,  as  it  is  technically  called, 
'  'sand. ' '  It  therefore  requires  a  comparatively  large  sur- 
face to  make  them  secure  against  the  weight  and  action 
of  melted  metal  during  the  process  of  pouring  it  into  the 
mold.  On  account  of  the  varying  shapes  and  conditions 
there  can  be  no  exact  rule  given  for  the  sizes  of  these 
prints,  that  will  cover  all  cases.  The  length  of  the  core 
prints  for  a  plain  cylindrical  horizontal  core  should 
approximate  its  diameter,  and  its  shape  should  be  that  of 
a  cylinder.  For  a  vertical  core  of  this  same  general 
shape,  the  print  should  be  the  frustrum  of  a  COne,  with  the 
large  end  next  the  pattern;  the  height  should  be  one 
inch,  and  the  diameter  of  the  small  end  one-half  inch  less 
than  the  large  end. 

In  core  work  that  requires  prints  of  other  shapes 
than  those  mentioned  above,  that  is,  where  the  opening 
.into  or  through  the  casting  is  not  round,  then  the  prints 
should  correspond  in  shape. 

The  making  of  core  prints  properly  located  and  of 
correct  size  and  shape  is  a  very  important  part  of  the 
pattern-maker's  art,  especially  so  from  the  molder's 
standpoint.  Prints  that  do  not  show  the  exact  position 
of  the  core  may  be  very  misleading  and  may  result  in  the 
loss  of  the  casting.  One  form  of  core  where  this  mistake 
might  easily  be  made  and  not  be  noticed  until  the  cast- 


CORES 


41 


ing  was  formed  is  illustrated  by  Fig.  11.  The  figure 
represents  a  casting  that  requires  a  cylindrical  horizontal 
core  with  a  part  enlarged  to  make  the  cavity  (A)  which, 
it  will  be  noticed,  is  not  in  the  center  of  the 
length  of  the  casting.  In  this  case  if  both  core  prints 
are  made  of  the  same  size,  the  molder  will  be  quite  likely 
to  set  the  core  wrong  end  to.  The  molder  would  not  be 
altogether  to  blame  for  this  mistake  as  he  generally  does 
not  have  anything  to  guide  him  in  this  work  except  the 
pattern  and  core  box  furnished  by  the  pattern-maker. 


l_ 


_T'"f  T 

T   1 

i    A    l£  ' 

/a1  3" 



LJj 

:±± 

FIG.  11. 

But  if  one  core -print  is  made  larger  than  the  other,  then 
it  will  be  impossible  for  him  to  set  it  incorrectly  without 
deliberately  cutting  the  mold.  In  all  core  work,  there- 
fore, the  prints  should  be  of  such  size  and  shape  that  it 
will  be  impossible  to  set  the  core  into  the  mold  in  any 
other  than  the  correct  way.  As  mentioned  above,  one 
method  is,  as  shown  in  Fig.  11,  to  make  one  print  larger 
than  the  other  or  of  a  different  shape.  For  cylindrical 


42  WOOD    PATTERN    MAKING 

cores,  the  first  is  of  course  the  best,  and  is  sure  to  accom- 
plish the  desired  result.  Sometimes  it  is  required  that 
a  cylindrical  core  should  lie  in  the  mold  in  a  certain 
position  with  regard  to  its  circumference.  In  that  case 
it  would  be  necessary  to  change  the  shape  of  at  least  one 
of  the  prints,  making  one  or  both  square  so  that  the  core 
cannot  be  set  wrong  or  revolve  after  being  set. 

Some  prints  for  horizontal  cores  are  not  made  long 
enough,  consequently  the  metal  when  poured  into  the 
mold  will,  by  its  own  static  pressure,  raise  or  displace 
the  core  and  make  the  casting  thinner  on  the  cope  side 
because  of  this  movement. 

It  is  advisable  to  make  the  prints  of  cylindrical  hor- 
izontal cores  about  equal  in  length  to  the  diameter  of  the 
core.  This  may  seem  excessive  and  in  some  cases  it 
may  be,  but  it  had  better  be  too  long  than  too  short. 
When  it  becomes  necessary  to  make  them  shorter  than 
this  on  account  of  the  size  of  the  flask  to  be  used,  or  of 
the  core  oven,  and  the  casting  is  quite  heavy,  it  is  good 
practice  to  imbed  a  plate  of  iron  in  the  mold  for  the  core 
to  rest  on,  thus  the  weight  of  the  core  will  be  distributed 
over  a  larger  area  of  sand  than  the  core -print  alone  would 
afford. 

A  great  many  castings  are  lost  because  the  lower 
print  of  vertical  cores  are  made  nearly  parallel  or  with  the 
ordinary  pattern  draft.  The  probable  cause  of  this  is 
that  the  core  does  not  go  down  to  the  bottom  of  the  mold 
since  the  sand  is  cut  down  by  the  core  on  setting.  So 
when  the  cope  is  closed,  being  too  long,  it  breaks  the 
mold  around  the  print  of  the  core,  allowing  metal  to  flow 
into  the  vent  and  thereby  causing  the  casting  to  "blow."' 
This  may  be  overcome  to  a  large  degree  by  tapering  the 
lower  print  as  is  usually  done  in  the  case  of  the  upper 


CORES  43 

one.  If  this  is  attended  to  there  can  be  no  trouble  in 
setting  the  core.  Indeed,  in  the  case  of  small  cores,  the 
molder  can  set  them  enough  faster  to  pay  for  the  extra 
work  of  pasting  such  cores  together.  As  this  is  the  main 
objection  to  this  shape  of  print,  viz.,  the  necessity  of 
making  the  cores  in  halves,  it  will  be  more  than  overbal- 
anced by  the  advantage  of  the  greater  facility  and  rapid- 
ity with  which  the  cores  can  be  set,  to  say  nothing  about 
the  larger  output  of  sound  castings. 

The  subject  of  taper  core -prints  for  vertical  cores  is 
one  of  considerable  importance,  especially  from  the 
molder's  standpoint.  It  is  well  to  adopt  some  standard 
taper,  so  that  if  a  core-print  is  lost,  another  may  be  made 
of  the  correct  size  whether  the  core  box  is  in  sight  or  not. 
Probably  the  best  taper  for  the  purpose  is  one  of  one- 
fourth  inch  to  one  inch  in  height.  This  is  an  easily 
remembered  taper  and  will  give  entire  satisfaction  to  the 
molder.  This  taper  can  be  employed  for  all  vertical 
prints  large  or  small,  (the  smaller  sizes  being  reduced  in 
length)  one  inch  is  long  enough  for  any  size  of  cylin- 
drical Vertical  core.  A  good  rule  to  follow  for  cores  less 
than  one  inch  in  diameter  is  to  make  the  length  of  the 
print  equal  to  the  diameter,  while  preserving  the  same 
taper.  It  might  be  objected  that  one  inch  is  too  short 
for  large  cores,  say  of  12  inches  or  more  in  diameter. 

But  there  is  not  much  strain  on  the  print,  that  is  on 
the  print  in  the  sand  of  the  mold  which  holds  the  core  in 
place, — for  it  simply  locates  the  core.  Nearly  all  the 
strain,  if,  to  be  sure,  there  is  any,  comes  on  the  end  of 
the  core.  Therefore,  any  extra  length  given  the  print 
would  be  of  no  advantage,  and  one  inch  is  as  good  as  a 
greater  length.  One  reason  why  there  is  but  a  slight 
strain  on  the  sides  of  these  prints  is  that  the  metal  on 


44 


WOOD   PATTERN    MAKING 


being  poured  into  the  mold  completely  surrounds  the 
core  so  that  the  pressure  is  practically  equal  in  all  direc- 
tions. This,  however,  is  not  the  case  with  the  horizon- 
tal cylindrical  core.  As  has  been  already  mentioned  a 
taper  of  one -fourth  inch  on  each  side  is  the  best.  This 
is  illustrated  in  Fig.  12,  where  it  is  reduced  to  a  system. 
In  this  system,  for  cores  that  are  less  than  one  inch  in 
diameter,  the  dimensions  of  the  print  are  derived  from 


FIG.  12 

the  diameter  of  the  core;  for  instance,  if  it  is  required  to 
provide  for  a  core  that  is  seven -eighths  inch  in  diameter, 
the  length  of  the  prints  will  be  seven -eighths  inch,  or 
the  diameter  of  the  core,  the  large  diameter  also,  seven  - 
eighths  inch,  the  small  diameter  seven -sixteenths  inch 
or  one -half  the.  large.  Therefore,  in  using  this  system, 
all  that  we  need  to  know  is  the  diameter  of  the  core,  and 
this  will  give  the  other  dimensions.  Now  if  a  print  is 
lost,  as  often  happens,  another  can  be  made  without 
seeing  the  core  box,  if  this  system  is  carried  out  for  all 
cores  of  this  kind. 


CHAPTER  VII. 

MOLDERS'    JOINTS    OR    PARTINGS. 


The  jointing  of  patterns  is  fundamental,  and  must  be 
considered  from  two  points  of  view ;  that  of  the  molder, 
and  that  of  the  wood -worker.  The  first  is  concerned 
more  particularly  with  the  removal  of  the  pattern  from 
the  mold,  or,  as  the  molder  expresses  it,  pulling  the  pat- 
tern. The  second  is  constructional,  and  into  it  enters  the 
combination  and  arrangement  of  the  different  pieces  of 
wood  composing  the  pattern.  The  joints  that  are 
arranged  for  the  purpose  of  removing  the  pattern  from 

the  mold  are  usually  called  partings,  or  pattern-makers' 

partings,  and  strictly  speaking,  are  not  joints.  The  joints 
made  in  the  construction  of  the  pattern  are  true  joints, 
and  should  be  made  as  nearly  perfect  as  possible,  since 
the  strength  and  durability  of  the  pattern  depends  largely 
on  their  efficiency  as  joints. 

The  first  mentioned  of  these  joints,  the  molder's  part- 
ings, will  be  considered  in  this  chapter.  Whether  a 
pattern  is  made  correctly  or  not,  from  the  molder's 
standpoint,  will  depend  largely  on  the  understanding 
that  the  pattern-maker  has  of  these  partings,  and  of 
their  position  in  the  mold  itself.  In  order  to  explain 
these  points  a  few  examples  will  be  mentioned.  It 
requires  at  least  one  of  these  molder's  partings  for  every 
pattern,  as  the  mold  must  consist  of  two  bodies  of  sand, 


HOLDERS'  JOINTS  OR  PARTINGS 


47 


so  that  the  pattern  may  be  taken  out.  The  simplest 
form  of  pattern  is  a  square  block  like  that  represented  by 
Fig.  13.  The  parting  will  be  made  on  the  line  A  B, 


FIG.  13.  FIG.  13  (a). 

the  part  of  the  mold  below  that  line  being  in  the  nowel ; 
in  this  case  all  the  mold  will  be  in  the  nowel,  the  cope 
forming  the  top  surface  only.  The  next  in  point  of 
simplicity  is  known  as  a  Simple  parted  pattern,  and  is 
represented  by  Fig.  1,  on  page  6.  In  a  mold  made  off 
this  pattern,  one -half  would  be  in  the  nowel,  and  one- 
half  in  the  cope,  as  represented  by  Fig.  13  (a).  The 
line  A  B  is  the  parting  line  of  the  mold  and  also  of  the 


FIG.  14. 

pattern.  In  this  form  of  pattern,  it  will  be  noticed,  the 
molder's  parting  and  the  pattern-maker's  parting  exactly 
coincide.  When  a  pattern  is  so  made  that  the  partings 
can  be  arranged  in  this  way,  the  molding  may  be  very 
easily  and  quickly  done.  The  process  of  molding  such 
a  pattern  is  described  in  Chapter  II.  Fig.  14  may  be 


48 


WOOD    PATTERN   MAKING 


considered  typical  of  a  large  class  of  pattern  work.  It  is 
a  pattern  for  a  small  car  wheel  having  a  central  web. 
The  molder's  parting  will  be  made  on  line  A  B.  No 
parting  is  required  in  the  pattern  except  that  the  boss,  or 
hub,  C,  is  usually  left  loose,  so  it  will  lift  with  the  cope. 
Fig.  15  represents  a  pattern  of  a  double  flange  wheel, 
and  is  a  good  example  of  a  class  of  patterns  where  the 
molder's  and  pattern-maker's  joints  do  not  coincide. 


r-n 

i     L. 

J 

FIG.  15. 
This  would  need  what  is  called  a  three-part  flask,  meaning 

that  the  mold  is  composed  of  three  distinct  bodies  of  sand, 

which,  of  course,  involves  the  making  of  two  molder's 
partings.  One  of  these  will  come  in  the  centre  of  each 
flange  or  lines  A  B  and  C  D.  The  pattern  will  be 
parted  at  E  F.  The  sand,  or  cores,  that  will  form  the 
part  of  the  mold  at  G  and  H  will  be  lifted  with  the  cope 


FIG.  16. 


down  to  the  upper  line  of  the  web.  The  mold  for  a  worm 
wheel  is  another  good  example  of  molding  where  the 
parting  of  the  pattern  does  not  coincide  with  that  of  the 
mold  Fig  16  will  make  this  quite  clear.  The  pattern 


HOLDERS'  JOINTS   OR    PARTINGS 


49 


will  be  parted  along  the  line  AB;  the  molder's  partings, 
of  which  there  must  be  two,  will  come  on  the  lines  C  D 
and  G  H.  All  of  the  teeth  will  come  in  the  middle  part, 
or  cheek,  included  in  the  space  K.  The  two  halves  will, 
of  course,  be  drawn  from  the  mold  in  opposite  directions, 
the  inner  curves  of  the  rim,  and  the  taper  of  the  hub, 
affording  plenty  of  draft.  There  is  another  form  of 
molder's  parting  known  as  an  "irregular  parting,"  that 
must  frequently  be  used  on  account  of  the  shape  of  the 
pattern.  The  pattern  represented  by  Fig.  17  is  an 
example  of  this  form  of  parting.  In  the  molding  of  this 
pattern  the  molder's  parting  will  be  made  along  the 


FIG.  17. 

dotted  line  DD,  so  that  the  most  of  the  mold  will  be  in 
the  nowel,  which  is  very  desirable,  as  it  leaves  less  to  be 
lifted  by  the  cope.  As  indicated  by  the  tapered  prints 


50 


WOOD   PATTERN    MAKING 


shown  at  A  and  B  in  Fig.  50,  a  core  will  be  used  for 
forming  a  round  hole  through  the  casting.  Another, 
but  a  more  simple  joint  of  this  kind  is  shown  by  Fig.  18, 
which  represents  a  cast-iron  bracket.  The  parting  of 


FIG.  18. 

the  mold  will  be  made  along  the  dotted  line  AB.  If  a 
number  of  comparatively  small  brackets  of  this  shape  is 
wanted,  the  pattern  can  be  parted  through  the  central 
web,  or  a  follow  board  can  be  made  and  fitted  to  a  one- 
piece  pattern. 


FIG.  19. 

A  contrivance  frequently   used  in  molding,    calle 
Skewering   On   loose  pieces,   saves   considerable   time   an 


HOLDERS'  JOINTS  OR  PARTINGS  51 

work  in  both  pattern  shop  and  foundry.  An  example  oi 
this  is  illustrated  by  Fig.  19,  which  represents  a  part  of 
a  cast-iron  base  for  a  wood -working  machine.  The 
whole  casting  is  cored  out;  and,  for  convenience  in 
molding,  the  pattern  was  boxed  up  to  form  a  one-piece 
pattern,  to  be  pulled  from  the  mold  in  the  direction  indi- 
cated by  the  arrow.  If  the  two  bosses,  A  and  B,  were 
fastened  on ,  they  would  tear  up  the  sand .  In  order  to  pre- 
vent this  they  are  Skewered  On.that  is,  held  in  place  tempor- 
arily with  wire'skewers,  as  shown.  As  the  mold  is  being 
rammed  up,  after  sand  enough  has  been  rammed  around 
the  bosses  to  hold  them  in  place,  the  skewers  are  pulled 


FjG-  20.  pIG.  21. 

aut.  This,  of  course,  allows  the  main  pattern  to  be 
oulled  out,  thus  leaving  in  the  mold  these  loose  pieces 
ivhich  can  be  pulled  sidewise  into  the  mold.  Of  course, 
his  pattern  could  be  parted  through  the  center  line,  but 
that  would  entail  a  large  amount  of  extra  work  in  both 


52  WOOD    PATTERN    MAKING 

the  foundry  and  the  pattern  shop.  By  the  use  of  this 
method,  therefore,  the  extra  work  of  making  another 
parting  is  saved.  Another  way  sometimes  adopted  for 
forming  projections  on  a  casting  is  made  clear  by  Figs. 
20  and  21.  They  represent  a  hollow,  cylindrical  cast- 
ing, with  a  flange  on  both  ends,  a  projecting  boss  for  a 
pipe  on  one  side  about  midway  of  its  height,  and  an 
opening  through  the  top.  The  pattern  will  have  to  be 
parted  on  the  line  CC,  and  will  require  a  three -part 
flask,  with  molder's  parting  along  line  BB.  To  form  the 
projection  on  the  side,  one  of  two  methods  may  be 
adopted:  One,  the  use  of  a  core  print  and  core;  the 

A 


FIG.  21. 

other  a  core  only,  to  be  set  in  place  at  the  time  of  ram- 
ming up  the  mold.  If  the  second  method  is  used,  all 
that  the  pattern-maker  needs  to  do  is  to  make  a  core  box 
with  a  pattern  projection  located  in  it. 

This  core  box  is  represented  by  Fig.  22.   If  the  first 
method  is  adopted,  a  core  print  will  have  to  be  put  on 


HOLDERS'    JOINTS   OR    PARTINGS  53 

the  side  of  the  pattern,  so  as  to  extend  from  the  top 
parting  down  to  a  point  just  below  the  projection  If  a 
hole  is  to  be  cored  through  the  projection,  this  would  be 
the  best  way  of  doing  the  job. 

The  examples  given  above  of  molder's  joints  do  not 
introduce  nearly  all  the  ways  and  means  employed  by  the 
molder  for  making  molds.  But  they  do  give  a  good  gen- 
eral idea  of  the  most  common  ways,  and  will  afford  such 
suggestions  to  the  beginner  in  pattern -making  as  to 
enable  him  to  make  patterns  so  that  they  can  be 
pulled"  without  injury  to  the  mold.  This  should  be 
the  first  consideration  of  the  pattern-maker,  as  on  it 
depends  in  >a  large  degree  the  accuracy  of  the  casting. 
If  the  mold  is  injured  in  any  way  by  the  pulling  of  the 
pattern,  so  that  the  molder  has  to  mend  it,  the  casting 
is  rarely  correct  in  shape.  In  the  next  chapter,  the  mat- 
ter of  constructional  joints  will  be  taken  up,  that  is,  the 
building  of  wood  patterns  from  the  view  point  of  the 
wood -worker. 


CHAPTER  VIII. 


CONSTRUCTIONAL  JOINTS 

In  a  consideration  of  this  part  of  the  general  subject 
of  pattern -making,  two  things  must  be  given  prominence, 
viz. :  the  strength  and  durability  of  the  pattern,  and  its 
permanence  of  form.  This  latter  is  very  likely  to  be 
interfered  with  by  the  absorption  of  moisture  from  the 
damp  sand,  thereby  causing  the  wood  to  swell,  and  per- 
haps to  warp.  The  amount  of  moisture  thus  absorbed 
depends  upon  the  time  the  pattern  has  to  remain  in  the 
mold,  and  upon  the  condition  of  its  protective  coating  of 
varnish.  To  overcome  any  change  likely  to  take  place 
from  this  cause,  several  methods  of  arranging  the  various 
pieces  of  which  the  pattern  is  built  up,  are  used.  The  par- 
ticular method  to  be  employed  in  a  given  case  depends 
on  the  size  and  shape  of  the  pattern,  and  also  depends, 
to  a  degree,  on  whether  a  large  number  of  castings  is 
wanted  or  only  one.  In  order  to  secure  the  requisite 
permanence  of  form,  it  is  better,  other  things  being  equal, 
to  build  a  pattern  of  several  pieces  rather  than  to  cut  it 
out  of  one  piece.  For  then  the  warping  in  the  whole 
pattern  is  reduced  to  a  minimum.  In  small  patterns, 
however,  this  warping  may  be  disregarded;  therefore,  a 
small  pattern  may  be  cut  from  a  single  piece  of  wood. 
This  matter  of  constructional  joints  may  be  most  easily 
comprehended  by  studying  examples  of  forms  likely  to 
be  required. 


56  WOODjPATTERN    MAKING 

When  thin  disks  are  wanted  it  is  best  to  build  them 
up  of  three  layers  with  the  grain  of  the  pieces  running 
tangentially  to  a  small  circle  in  the  center,  as  illustrated 
by  Figs.  23  and  24.  The  grain  of  the  wood  must  run 


FIG.  23.  FIG.  24. 

lengthwise  and  parallel  to  the  longest  side  of  each  sector. 
After  the  pieces  have  been  fitted  together,  a  groove  is 
cut  in  the  edge  of  each,  in  which  tongues  of  wood  are 
glued  and  driven  as  illustrated  by  Fig.  24.  When  one 
disk  has  been  glued  up  and  the  glue  has  dried,  the  sec- 
tors for  the  other  disks  may  be  glued  directly  to  it  with 
the  joints  running  across  the  others,  the  angle  depending 
on  the  number  of  sectors  used  to  form  the  circle.  This 
makes  a  very  rigid  construction  and  one  which  will  no 
warp. 

If  in  building  a  pattern  a  thin,  wide  board  is  required 
and  the  other  parts  of  the  pattern  are  of  su.ch  shape  that 
they  do  not  afford  to  it  sufficient  support  to  keep  it  from 
warping,  a  good  way  is  to  rip  the  board  up  into  strios  of 


CONSTRUCTIONAL  JOINTS  57 

from  two  to  four  inches  wide  (according  to  the  width  of 
the  required  board)  and  then  glue  the  strips  together 
with  each  alternate  strip  reversed,  as  shown  in  Fig.  25. 
In  this  way  the  warping  will  be  reduced  to  the  minimum 
because  the  alternate  pieces  are  inclined  to  warp  in  oppo- 
site directions. 

A  good  way  to  support  patterns  of  this  general  shape 
during  the  process  of  molding  is  illustrated  by  the  lower 
part  of  Fig.  25.  The  additional  pieces  B  and  C  are  called 
counter  ribs.  The  recesses  made  by  them  in  the  sand  will 
be  filled  by  the  molder,  or,  as  he  expresses  it,  they  are 
"stopped  off  in  the  mold."  The  shape  of  these  counter 
ribs,  which  is  more  clearly  shown  at  D,  indicate  to  the 


FIG.  25. 

molder  that  they  are  to  be  stopped  off  in  the  mold.  When- 
ever possible  these  should  be  put  on  the  pattern  so  they 
will  come  in  the  nowel  of  the  mold ;  these  are  also  called 
"stop-off"  pieces.  Another  way  of  building  patterns 
that  are  round  and  flat  and  are  supported  by  segments 
running  around  them,  is  to  make  the  flat  part  of  several 
strips  rather  than  of  a  wide  board.  This  is  illustrated  by 
J  >  r  i  ese  strips  should  not  be  glued  together,  but 


58 


WOOD   PATTERN    MAKING 


held  in  position  by  the  segments  that  are  built  on  to 
them.  If  the  pattern  is  more  than  12  inches  in  diame- 
ter on  the  inside,  it  is  advisable  to  insert  at  least  one 
dowel  in  each  of  the  joints  between  these  strips  to  keep 


FIG.  26. 

them  from  springing  sidewise.  This  need  be  done  only 
for  three  or  four  of  the  joints  near  the  center.  A  "slip" 
tongue  joint  may  also  be  used  instead  of  dowels.  An- 
other way  to  overcome  the  effect  of  shrinking  and  swell- 
ing in  large  patterns  is  the  use  of  what  is  termed  open 

joints. 


FIG.  27 


If  it  is  required  to  build  a  large  pattern   that  is  flat 
and   comparatively   thin,    either   circular   or   square,  it 


CONSTRUCTIONAL  JOINTS  59 

would  be  built  as  shown  by  Fig.  27;  that  is,  the  sides 
would  not  be  built  up  by  gluing  narrow  boards  together, 
but  they  would  be  laid  side  by  side  with  open  joints 
between,  of  from  one -sixteenth  inch  to  one -eighth  inch 
in  width,  and  a  slip  tongue  inserted.  If  the  boards 
expand  with  moisture  the  width  of  the  pattern  as  a  whole 
does  not  increase ;  the  only  effect  is  to  partly  close  these 
open  spaces.  If  the  boards  shrink  the  only  effect  is  that 
the  spaces  increase  in  width.  As  broad -plated  work  is 
usually  stiffened  with  ribs  and  flanges,  the  fact  that  the 
joints  are  open  will  not  lessen  the  rigidity  of  the  pattern. 
If  a  case  should  occur  where  there  could  not  be  support 
enough  in  the  pattern  itself,  then  the  boards  could  be 
held  in  place  as  shown  in  Fig.  27,  by  a  method  which 
is  practically  paneling.  A  frame  is  made  as  for  a  panel 
door,  and  the  ends  of  the  boards  fitted  to  a  groove. 

This  method  may  be  used  in  connection  with  what 
is  known  as  boxing  up  a  pattern.  This  is  illustrated  in 
Fig.  28.  Open  joints  are  represented  at  a,  a,  a,  Fig.  27. 
This  method,  boxing  up,  is  frequently  used  for  large  pat- 
terns which  if  made  solid  would  be  unduly  heavy  and 
would  be  especially  liable  to  become  affected  by  mois- 
ture and  dryness.  The  rebated  joint  should  always  be 
used  at  the  corners  in  boxing  up  a  pattern  that  is  of  a 
square  or  rectangular  cross  section.  This  is  illustrated 
by  Fig.  28.  If  the  pattern  was  to  be  pulled  from  the 
mold  in  the  direction  indicated  by  the  arrow,  and  was 
built  as  at  (a)  Fig.  28,  then  any  change  due  to  shrinking 
or  swelling  of  the  relative  position  of  pieces  b  and  c 
would  leave  an  uneven  surface  on  the  vertical  side  which 
on  being  pulled  from  the  mold  would  be  likely  to  tear  up 
the  sand  and  thereby  cause  the  molder  some  trouble 
If  the  joints  are  arranged  as  at  (A)  Fig.  28  this  cannot 


60 


WOOD    PATTERN    MAKING 


occur.  This  form  of  joint  has  another  advantage,  for  if 
the  joint  were  simply  a  butt  joint,  the  ramming  of  the 
sand  of  the  cope  down  on  the  face  (E)  would  be  likely  to 
drive  the  top  board  down  below  the  edges  of  the  sides, 
but  in  this  case,  the  piece  E,  being  rebated  into  A  and  C, 
cannot  be  driven  down. 

Fig.  29  represents  an  example  of  another  type  of 
hollow  work,  which,  however,  is  not  called  boxing  up, 
but  lagging  or  lagging  up.  This  method  may  be  defined 
as  the  building  of  patterns  with  longitudinal  strips  that 
run  parallel  with  the  axis  of  the  proposed  cylinder.  It 
is  used  for  turned  work.  The  figure  represents  a  sec- 
tion of  the  pattern  of  a  pipe  or  column  of  any  diameter 
ver  four  or  five  inches.  A  A  is  the  joint  of  both  pat- 


FIG.  29 

tern  and  mold.  B  B  are  cross  bars  of  polygonal  shape 
on  which  the  strips  or  lags  are  laid  and  fastened  with 
glue  and  screws.  The  lags  are  also  glued  to  each  other 
except  on  the  line  A  A. 

Fig.  30  illustrates  another  way  of  building  by  lag- 
ging. In  this  way  much  narrower  strips  are  used,  there- 
by reducing  the  work  of  turning  and  also  requiring  less 
lumber.  The  parts  for  the  core  prints  are  built  up  first, 
and  then  the  lags  for  the  rest  of  the  pattern  are  fitted  an 


CONSTRUCTIONAL  JOINTS 


61 


glued  and  screwed  to  these,  as  is  indicated  by  the  figure. 
Should  the  body  of  the  cylinder  be  long,  two  or  more 
semicircular  discs  must  be  used  to  insure  rigidity.  Fig. 
31  shows  how  this  method  of  building  up  may  be  used 
for  large  cylindrical  core  boxes.  If  the  work  is  done 
accurately,  the  work  of  finishing  the  inside  of  the  box  is 
reduced  to  a  minimum. 


FIG.  30. 


FIG.  31. 


When  annular  patterns  of  six  inches  or  more  in 
diameter  are  wanted  they  are  made  by  what  is  known  as 
building  up  With  Segments.  This  is  illustrated  by  Fig.  32, 
and  when  properly  done  makes  a  very  strong  construe  •« 
tion.  The  several  pieces  should  be  cut  from  the  board 
in  such  a  way  that  the  grain  of  the  wood  follows  the 
circle  as  near  as  may  be.  Therefore,  in  laying  out  the 
segments  the  chords  of  the  curves  should  be  parallel  to 
the  grain  of  the  wood.  In  building  patterns  of  this  type, 
a  number  of  short  segments  are  sawn  out  and  glued  in 


62  WOOD   PATTERN   MAKING 

courses,  one  over  the  other  with  the  end  joints  alternat- 
ing or  breaking  joint,  when  the  glue  is  dry  the  correct 
outline  is  imparted  by  turning  or  otherwise.  By  this 
construction  shrinkage  in  the  segments  is  reduced  to 
practically  nothing. 


FIG.  32. 

Bxamples  of  constructional  joints  of  still  another 
type  of  patterns,  sometimes  termed  plate  work,  is  repre- 
sented by  Figs.  33  and  34.  Fig.  33  shows  a  frame 
cut  from  solid  wood,  18  inches  wide  and  2  feet  6  inches 
long,  by  1  inch  thick.  It  is  clear  that  strength  and  per- 
manence of  form  is  entirely  lacking  in  bars  (a  a). 
Contrast  the  construction  in  Fig.  34.  In  this  there  can- 
not be  any  material  alteration  in  width  or  length,  in  gen- 
eral or  local  dimensions,  and  there  is  the  maximum  of 
strength.  The  frame  is  made  of  five  narrow  strips. 
Alternative  methods  of  making  half  lap  points  are  shown. 
At  the  corners  plain  halving  is  shown.  At  D  the  dove- 
tailed form  of  halving  is  illustrated.  The  plain  halving 
if  properly  made,  glued  and  screwed,  is  very  strong 


CONSTRUCTIONAL  JOINTS 


63 


and  permanent.      For  standard  patterns,  however,  it  is 
advisable  to  employ  the  dove -tail  form. 

Another  example  of  this  same  type,  but  of 
a  very  distinct  form,  is  shown  by  Fig.  47.  The 
finished  casting  is  shown  by  Fig  46.  It  will  be 
noticed  that  the  joints  are  of  the  half -lap  form.  This 
figure  (Fig.  47)  shows  the  plate  part  of  the  pattern  only, 


FIG.  33.  FIG.  34. 

made  up  of  three  pieces.  The  pieces  are  so  arranged 
that  wherever  there  is  a  curve  there  is  wood  with  the 
grain  running  practically  tangent  to  it;  consequently,  if 
the  joints  are  properly  made  and  glued,  it  can  be  worked 
into  shape  without  being  broken  out.  Moreover,  there 
is  wood  enough  at  all  the  angles  so  that  the  fillets  may 
be  worked  in  the  solid  wood  instead  of  separate  pieces 
being  glued  in  for  the  fillets.  For  standard  plate  work 
it  is  always  best  to  do  this,  even  if  it  does  take  wider 
material.  The  added  durability  will  more  than  pay  for 


64 


WOOD   PATTERN   MAKING 


the  extra  lumber,  and  then  it  also  saves  the  time  of  mak- 
ing and  gluing  in  the  separate  pieces. 

Round  corners  maybe  formed,  as  shown  by  Fig.  35. 


FIG.  35. 

In  this  case  the  two  pieces,  A  and  B  are  joined  in  the 
usual  way  with  a  butt  joint  as  at  C;  the  piece  D  is  glued 
into  the  angle  and  allowed  to  stand  long  enough  to  dry ; 
then  the  corner  is  worked  to  the  required  form  outside 
and  inside.  In  work  of  this  kind  it  is  best  to  work  the  inside 
first,  because  the  piece  can  usually  be  held  better  if  the 
outside  corner  is  square,  than  if  it  is  rounded.  The 
block,  after  being  fitted  to  the  angle,  may  be  sawed  or 
planed  to  form,  as  indicated  by  lineE.  This  can  be  done 
more  easily  before,  than  after  it  is  glued  in  place. 

As  pattern -making  is  one  of  the  most  comprehensive 
of  trades,  and  the  demands  of  the  engineering  profession 
for  complicated  castings  are  limitless,  it  is  impossible  to 
anticipate  the  next  form'a  pattern-maker  will  be  called  on 
to  make.  This  being  the  case,  only  general  methods  can 
be  considered  in  a  volume  of  this  size,  treating  on  the 
subject.  The  joints  and  methods  of  construction  that 
have  thus  far  been  considered  are  those  most  frequently 
employed  in  pattern  -making.  Special  examples  of  types 
of  pattern -making  will  next  be  taken  up,  for  which  one 
or  more  methods  of  construction  will  be  given  in  detail. 


Clement  Universal  Bench  Saiv 


Williamsport  Scroll  Saw 


CHAPTER  IX. 


SPECIAL  TYPES  OF  PATTERNS. 


Before  taking  up  the  subject  of  making  special  types 
of  patterns,  certain  matters  that  apply,  not  only  to  special 
types,  but  to  all  patterns,  must  be  considered. 

One  of  these  is  the  preparation  of  the  lumber. 

This  consists  in  the  first  place  of  cutting  roughly  to 
size,  the  several  pieces  required  for  making  the  proposed 
pattern.  They  are  then  allowed  to  stand  for  as  long  a 
time  as  the  job  will  allow,  so  that  they  may  warp  into 
and  assume  a  nearly  permanent  form.  If  this  is  done, 
when  they  are  cut  to  the  final  shape,  they  will  not  again 
warp  and  change  the  original  form  of  the  pattern.  This 
additional  seasoning  is  necessary,  because  lumber  will 
change  more  or  less  in  shape,  when  much  of  it  is  cut 
away,  exposing  a  surface  that  has  heretofore  been  on  the 
inside  of  the  plank  or  board.  The  foregoing  constitutes 
the  first  step  and  may  be  termed  Cutting  the  Stuff  roughly  tO 
SiZC.  The  next  step  is  planing  up  one  or  two  sides  to  a 
true  plane,  and  marking  them  as  Working  faces.  Usually 
these  planes  should  be  made  at  right  angles  to  each 
other.  This  is  quite  important,  as,  generally  speaking, 
the  accuracy  of  the  work  will  depend  to  a  degree  upon 
the  accuracy  of  these  two  faces.  All  lumber  to  be  used 
in  making  patterns  should  be  planed  by  hand  before 
being  put  into  the  pattern,  especially  if  a  flat  surface  is 


67 


SPECIAL  TYPES   OF   PATTERNS 

desired.  The  ordinary  rotary  knife  planer  will  not  plane 
stuff  flat,  therefore  the  hand  plane  must  be  used.  If 
there  is  a  Daniels  planer  in  the  shop  it  may  be  used  to 
plane  one  side  of  the  board ;  the  other  may  be  passed 
through  the  ordinary  planer.  But  even  if  this  is  done 
the  lumber  should  be  planed  by  hand  to  insure  a  good 
finish,  as  the  rotary  knife  will  leave  the  surface  more  or 
less  corrugated. 

The  simplest  patterns  are  those  which  are  made  in 
one  piece,   and  which  require  no  coring,  although  the 


F  all  over 


FIG.  36. 


FIG  37. 


castings  themselves  may  be  hollow.  In  commencing  a 
pattern,  one  must  first  decide  how  it  is  to  be  removed 
from  the  sand,  and  where  the  parting  line,  if  one  is 
needed,  should  be. 

A  simple  one -piece  pattern,  around  which  to  form  a 


68  WOOD   PATTERN   MAKING 

mold  with  a  dry  sand  core,  is  exemplified  by  the  stuffing 
box  gland  shown  in  Fig.  36.  This  figure  shows  the 
finished  casting,  which  is  to  be  finished  all  over. 

This  is  a  type  of  a  very  large  class  of  patterns 
which  must  be  cast  on  end.  It  is  what  is  generally 
known  as  a  stuffing  box  gland.  The  finished  casting  is 
represented  by  Fig.  36,  the  finished  pattern  by  Fig.  37, 
and  the  requisite  core  box  by  Fig.  38.  Fig.  36  repre- 
sents also  the  drawing  that  would  be  sent  to  the  shops. 
The  gland  is  made  from  this  drawing. 

Considering  this  pattern  from  the  molder's  stand- 
point, it  is  clear  that  if  it  is  molded  endwise,  with  the 
flange  up,  and  if  the  molder's  parting  is  made  along  the 
top  of  the  flange,  it  can  be  readily  pulled.  The  draft  in 
this  case  should  be  one -eighth  inch  for  12  inches.  Each 
core  print  should  be  one  inch  long.  When  the  amount  of 
draft  and  finish  is  decided  on,  it  is  a  good  plan  to  make  a 
full  size  sketch  of  the  pattern  as  it  will  appear  when 
ready  for  the  molder,  and  with  all  required  dimensions 
plainly  shown  on  it.  This  should  be  done  before  one 
begins  to  make  the  pattern.  Indeed,  one  may  well  fol- 
low this  in  the  case  of  every  pattern,  for  thereby  many 
mistakes  and  much  loss  of  time  will  be  avoided.  Accord- 
ing to  the  drawing  Fig.  36,  this  gland  is  to  be  finished 
all  over,  so  that  in  making  the  pattern  there  must  be 
allowance  for  both  finish  or  machining,  and  draft.  As 
none  of  the  dimensions  are  over  six  inches  in  any  one 
direction,  shrinkage  may  be  disregarded.  As  this  pat- 
tern is  to  be  pulled  from  the  mold  endwise,  the  draft  on 
the  outside  will  have  to  be  like  that  shown  by  Fig.  3, 
on  page  14.  One  way  to  make  a  pattern  for  this  casting 
is  shown  in  Fig.  36  (a).  If  it  is  made  in  this  way,  it 
may  be  molded  and  leave  its  own  core,  but  the  hole  can- 


SPECIAL  TYPES   OF    PATTERNS 


69 


not  be  made  parallel.  It  is  usual  to  allow  double  the 
amount  of  draft  on  the  inside  for  all  small  cores  similar 
to  this  one.  This  would  make  considerable  more  work 
for  the  machine  shop  if  the  hole  had  to  be  finished.  For 
this  reason,  if  a  large  number  was  wanted,  the  pattern 
would  be  made  as  described  in  the  following  pages : 

To   make  this  pattern  it  will  be  necessary  to  build 


FIG.  36  (a) 

up  a  block  of  wood  that  is  at  least  3^x3^x7  inches 
long.  The  best  way  to  do  this  is  to  use  two  pieces  1/4 
inches  thick,  and  one  piece  three -fourths  inch  thick,  glu- 
ing them  all  together,  with  the  thinner  one  in  the  middle. 
In  gluing  up  work  of  this  kind,  it  is  always  best  to  have 
the  thicker  pieces  on  the  outside;  for  if  the  piece  on  the 
outside  is  too  thin,  it  will,  during  successive  moldings, 
be  likely  to  become  loosened  on  account  of  the  action  of 
the  damp  sand  on  the  glue.  As  soon  as  the  glue  is  quite 
dry,  the  corners  may  be  cut  off  with  an  axe  or  a  chisel 
and  mallet.  The  piece  is  now  ready  to  be  mounted  in 
the  lathe,  and  should  be  turned  to  a  cylinder  of  three 
and  five-eighths  inches  in  diameter,  which  is  the  out- 
side dimensions  of  the  flange.  Now,  laying  a  rule 
along  the  tool  rest  up  against  the  cylinder,  point  off  the 
measurements  as  indicated  by  the  drawing,  preferably 


70  WOOD   PATTERN    MAKING 

commencing  at  the  right  hand  end,  that  is,  next  to  the 
back  or  dead  center  of  the  lathe.  By  commencing  at 
that  point  any  surplus  material  will  be  left  at  the  other 
end,  so  that  it  will  not  be  necessary  to  get  so  close  to  the 
chuck  or  driving  center  with  the  tools.  First,  then, 
make  a  mark  about  one -sixteenth  inch  from  the  right 
hand  end  for  the  end  of  the  print.  From  this  point 
measure  one  inch  for  the  length  of  the  print ;  from  this 
measure  three  and  three -fourth  inches  for  distance  from 
the  end  of  the  pattern  to  the  under  side  of  the  flange ; 
from  this  point  measure  three -eighths  inch  for  the  thick- 
ness of  the  flange ;  from  this  mark  measure  one  inch  for 
the  length  of  the  print  on  this  end.  Check  up  by  measur- 
ing total  length  between  the  outside  marks,  which  should 
be  six  and  one -eighth  inches.  Now  hold  the  point  of  a 
pencil  at  each  of  these  marks,  allowing  the  side  of  the 
pencil  to  lay  on  the  tool  rest ;  give  the  belt  of  the  lathe  a 
pull  which  will  turn  the  cylinder,  making  a  mark  all  the 
way  around  it.  Now  cut  the  cylinder  to  the  required 
size  below  the  flange,  remembering  that  the  core  prints 
will  have  to  be  tapered,  because  this  will  be  a  vertical 
core.  Now,  if  the  successive  steps  have  been  done  cor- 
rectly, the  pattern  will  be  like  Fig.  37.  The  top  print 
should  be  loose  for  the  convenience  of  the  molder.  All  the 
lathe  work  on  this  pattern  should  be  done  with  scraping 
tools,  except  that  the  gouge  should  be  used  for  roughing 
it  to  the  approximate  diameter. 

The  next  thing  will  be  the  making  of  the  core  box 
in  which  to  make,  or  form,  or  mold  the  dry  sand  core. 
This  box  is  shown  by  Fig.  38.  This  being  a  symmetri- 
cal core,  one  half  box  will  be  enough.  To  make  this 
we  proceed  as  follows :  Take  a  piece  of  straight -grained 
pine,  of  such  a  width  that  after  the  semicircular  groove 


SPECIAL  TYPES   OF   PATTERNS  71 

forming  the  body  of  the  box  is  cut  out,  there  will  be  left 
about  three-fourths  inch  on  each  side.  In  this  case,  the 
box  being  two  and  one -quarter  inches  in  diameter, 
and  one  and  one -half  inches  for  the  two  sides,  the  width 
of  the  piece  will  be  three  and  three -fourths  inches.  The 


FIG.  38.  FIG.  39. 

depth  of  the  groove  will,  of  course,  be  one  and  one- 
eighth  inches,  and  there  should  be  at  least  seven -eighths 
inch  thickness  of  wood  below  this,  which  will  make  the 
required  block  2x3^6  inches  and  five  inches  long. 
The  block  should  be  planed  on  all  sides ;  one  of  the  wide 
sides  (for  the  top  of  the  box,)  and  its  adjacent  narrow 
sides  are  to  be  straight  and  exactly  at  right  angles  to 
each  other.  To  lay  out  the  lines  for  this,  fasten  the 
block  in  the  vise  with  one  end  down  even  with  the  top  of 
bench,  or  vise.  Now  set  the  dividers  to  the  radius  of 
the  required  curve,  one  and  one-eighth  inches,  and  put 
one  leg  of  the  dividers  in  between  the  block  and  the  vise 
jaw,  on  the  side  intended  for  the  top  of  the  box,  approxi- 
mately in  the  center  of  the  side;  then  describe  a  semi- 
circ  e  on  the  end  of  the  block,  as  shown  at  Fig. 


72 


WOOD    PATTERN    MAKING 


39.  Now  with  the  gauge  set  to  the  distance  c  to  a, 
make  a  mark  along  the  top  or  face  side  for  the  whole 
length  from  the  point  a,  then  extend  the  gauge 
to  point  b,  making  another  line  the  whole  length 
of  the  block.  On  the  other  end  make  another 
semicircle.  This  completes  the  laying  out  of  the  core 
box  The  wood  must  now  be  taken  out  just  to  these 
lines.  This  may  be  done  in  two  ways,  the  better  of  which 
is  by  the  use  of  the  core  box  plane.  This  is  a  plane  whose 
face  instead  of  being  just  one  surface,  is  composed  of 
two  surfaces  set  at  right  angles  to  each  other,  as  shown 
by  Fig.  40.  The  cutting  iron  is  narrow,  and  ground  to 


FIG.  40. 

an  acute  angle,  so  as  to  conform  to  the  shape  of  the  plane 
at  the  apex  of  the  angle  forming  the  two  sides  of  the  face 
of  the  plane.  The  principle  of  its  construction  and  use 
is,  that  the  greatest  inscribed  angle  in  a  semicircle  is  a 
right  angle.  The  whole  of  the  wood  on  the  inside  of 
semicircle  cannot  be  cut  out  with  this  plane,  so  first 
use  a  gouge  to  cut  it  out  to  within  one -eighth  inch  of 
the  mark ;  then  cut  it  exactly  to  line  along  both  gauge 
marks;  then,  holding  the  plane  in  such  a  way  that 
the  fingers  of  the  left  hand  will  form  a  guide  to  keep  the 
plane  to  the  line,  cut  a  shaving  along  the  line  on  the  side 


SPECIAL  TYPES  OF   PATTERNS  73 

farthest  from  the  operator.  This  is  illustrated  by  Fig.  41 , 
in  which  the  upper  curved  line  represents  the  work  as 
done  by  the  gouge,  and  the  semicircle  immediately  below 
it  is  the  circle  to  which  the  work  is  to  be  cut.  There  is 
now  a  guide  for  both  sides  of  the  plane,  so  that  by  exer- 
cising a  little  care  the  plane  may  be  passed  along  through  - 


FIG.  41. 

out  the  length  of  the  block,  cutting  a  shaving  at  each 
stroke.  This  may  be  continued  until  about  one-third  of 
the  whole  is  worked  out.  Now  the  block  may  be  turned 
end  for  end,  and  the  other  side  treated  in  the  same  way 
down  to  about  midway  of  the  distance;  then  turn  the 
block  again  and  finish  the  other  side.  This  will  make  a 
very  neat  and  accurate  job  if  the  plane  is  in  proper  con- 
dition. Another  way  by  which  the  plane  may  be  started 
is  to  nail  a  thin  strip  of  wood  along  the  gauge  line  as 
represented  at  (a)  Fig.  41.  This  is  used  as  a  guide  for 
the  plane.  After  the  groove  has  been  cut  down  a  short 
distance  (about  one -sixteenth  inch),  this  extra  piece 
must  be  removed  to  the  other  side  and  again  used  as  a 
guide.  This  guide  piece  must  be  taken  away  before  work- 


74  WOOD    PATTERN    MAKING 

ing  the  groove  down  very  much,  for  if  allowed  to  remain 
it  would  change  the  size  of  the  semicircle  made  by  the 
plane.  The  cutting  iron  of  the  plane  should  be  so 
sharpened  and  set  as  to  cut  on  one  side  only,  preferably 
on  side  A,  Fig.  40.  If  it  is  allowed  to  cut  on  the  other 
side,  and  used  as  indicated  by  Fig.  41,  it  will  cut  the 
groove  too  large,  making  the  core  box  larger  in  diameter 
than  wanted.  Another  way  to  cut  out  this  part  of  the 
core  box  is  to  use  a  gouge  to  remove  almost  all  the 
material,  using  a  round  plane  to  finish  with.  Doing  the 
job  in  this  way  will  involve  the  use  of  a  straight  edge  to 
test  the  straightness  of  the  work  from  end  to  end.  For 
this  purpose,  a  straight  edge  with  a  thin  cross  section  is 
necessary.  A  try-square  if  long  enough,  is  a  very  good 
tool  for  this  purpose. 


Fig.  41  (a). 

It  will  be  a  great  advantage  to  set  the  cutting  iron  so 
it  will  cut  the  wood  on  one  side  of  the  plane  only.  In 
order  to  do  this  it  is  best  to  cut  away  a  small  amount  of 
wood  on  one  side  of  the  plane,  as  indicated  at  A  Fig.  40. 
This  plane  is  almost  indispensable  for  making  core  boxes 
of  the  shape  represented  by  Fig.  41  (a) ,  for  what  may  be 


SPECIAL  TYPES   OF   PATTERNS  75 

called  conical  cores.  As  the  curve  changes  continually 
throughout  the  entire  length,  it  is  almost  impossible  to 
make  a  cavity  that  is  uniform,  if  one  uses  the  gouge  and 
round  plane.  A  straight  edge  and  templet  must  be  used 
frequently  to  test  the  work.  But  the  core  box  plane 
overcomes  all  these  difficulties,  and  if  only  the  two  sides 
of  the  cavity  are  correctly  located,  and  then  worked  to 
the  lines  with  the  gouge,  the  plane  will  do  the  rest  of 
the  work.  There  are  machines  on  the  market  which  do 
this  kind  of  work  very  accurately  and  rapidly.  One  of 
them  is  illustrated  on  page  45.  This  is  the  Crane  Core 
Box  Machine. 

Whichever  method  is  used  in  making  this  part  of 
the  core  box,  it  needs  to  be  smoothed  on  the  inside  with 
sandpaper.  If  the  box  is  small,  this  is  best  done  with 
sandpaper  placed  around  a  cylinder  of  wood,  the  cylinder 
being  about  one -fourth  inch  smaller  in  diameter  than  the 
box.  If  the  box  is  large,  a  piece  of  wood  about  four  or  five 
inches  wide  and  an  inch  thick,  with  one  side  planed 
approximately  to  the  curve  of  the  inside  of  the  box,  will 
be  better. 

To  form  the  ends  of  the  box  marked  A  A  in  Fig.  38, 
the  following  is  the  best  way :  Make  two  pieces  of  wood 
four  inches  long  and  two  inches  wide,  and  exactly 
one  inch  thick.  Plane  them  so  that  two  of  the  narrowest 
faces  will  make  a  good  joint  at  right  angles  to  the  wider 
sides.  Now  face  up  a  chuck  about  six  inches  in  diam- 
eter, and  while  it  is  revolving  in  the  lathe,  make  a  fine 
pencil  mark  or  dot  in  the  center.  Place  one  of  the  pieces 
flat  on  the  chuck,  so  that  one  of  the  face  edges  will  pass 
through  this  dot  mark;  nail  it  to  the  chuck  in  this  posi- 
tion, and  then  place  the  other  piece  alongside,  and  nail 
it  also.  If  this  work  is  correctly  done,  the  chuck,  with 


76  WOOD    PATTERN    MAKING 

pieces  nailed  on,  will  look  something  like  Fig.  42.  This 
is  now  to  be  put  on  the  lathe,  and  a  hole  of  the  shape  of 
the  core  print  on  the  pattern  turned  into  it.  If  the 
blocks  were  properly  placed,  each  will  have  a  semicircular 
hole  in  it,  representing  one -half  the  frustrum  of  a  cone, 
whose  dimensions  correspond  exactly  with  those  of  the 
core  print  on  the  pattern.  These  are  now  to  be  taken 
from  the  chuck  and  nailed  and  glued,  one  on  each  end  of 
the  body  of  the  box  previously  made.  This  must  be  cut 
to  the  exact  length  required,  which  in  this  case  will  be 
four  and  one -fourth  inches.  It  is  necessary  that  a  core 
box  for  a  vertical  core  should  be  about  one -eighth  inch 


Fig.  42. 

longer  than  the  pattern,  so  that  the  cope  of  the  mold  will 
be  sure  to  fit  tightly  around  the  core ;  then  no  metal  can 
flow  up  alongside  of  it  and  over  the  end  of  the  core, 
thus  covering  up  the  vent  and  causing  the  casting  to 
blow.  For  the  above  reason  all  Vertical  cylindrical  cores 
should  be  one -eighth  inch  longer  than  the  total  length 
of  the  pattern  and  prints.  To  complete  the  box  it  is  only 
necessary  to  nail  pieces  (B  B.  Fig.  38)  one  on  each  end, 
and  then  give  a  taper  at  the  point  C.  To  make  the  core, 


SPECIAL  TYPES   OF    PATTERNS 


77 


two  halves  are  made  in  this  box;  after  drying,  they  are 
pasted  together,  making  a  complete  core. 

The  next  example  is  very  similar  to  the  former  one, 
but,  having  a  flange  at  both  ends,  it  will  have  to  be 
molded  horizontally,  and  will  therefore  require  a  horizontal 
core  The  completed  casting  is  represented  by  Fig.  43, 
and  a  pattern  for  producing  it  by  Fig.  44.  On  account 


FIGS.  43. 


FIG.  44. 


FIG.  45. 


of  the  shape  of  this  casting  it  will  be  best  to  make  the 
pattern  a  parted  pattern.  This  will  save  the  molder  some 
time  and  work,  as  it  will  give  a  form  that  is  easily 
removed  from  the  sand.  In  making  this  pattern,  the 
first  thing  to  do  will  be  to  get  two  pieces  of  wood  of  such 
dimensions  that  when  they  are  put  together  the  pattern 
can  be  turned  out  of  them.  As  will  be  noticed  by  the 


78  WOOD   PATTERN   MAKING 

drawing,  there  is  no  finish  required  except  on  the  face 
of  the  flanges.  Allowing  for  finish,  the  length  of  the 
pattern  without  the  core  prints  will  be  six  and  one- 
fourth  inches.  The  core  is  to  be  one  and  one -half  inches 
in  diameter,  so  the  prints  will  be  one  and  one-half  inches 
long;  then  two  inches  more  must  be  added  for  fastening 
together  at  the  ends,  making  a  total  of  eleven  and  one- 
fourth  inches  for  rough  size.  Two  pieces  then  are 
needed,  eleven  and  one -fourth  inches  long,  four  inches 
wide  and  two  inches  thick.  The  next  step  will  be  to 
plane  one  of  the  larger  sides  of  each  piece  to  a  true  sur- 
face, to  form  a  joint  between  them. 

The  next  thing  is  to  locate  the  holes  for  the  pattern 
pins  that  will  be  necessary  to  locate  the  two  halves  in 
relation  to  each  other  after  being  separated.  The  most 
practical  way  to  do  this  is  as  follows :  On  the  plane  sur- 
face of  one  of  the  pieces  locate  these  holes  with  a  pencil 
mark;  this  mark  to  be,  say  four  and  five  inches  from  a 
center  line  approximately  on  the  center  of  the  width.  If 
the  pins  are  thus  located,  the  molder  will  not  err  in 
putting  the  two  halves  together,  for  if  he  happens  to  do 
it  incorrectly,  he  will  at  once  recognize  his  mistake. 

Having  marked  the  points  where  it  is  desired  to  put 
the  pins,  take  two  small  brads  and  lay  them  on  the 
block  with  the  heads  at  these  points ;  now  carefully  lay 
the  other  piece  on  these  brads,  and  having  brought  it  into 
exactly  the  desired  position,  strike  the  top  piece  a  light 
blow  with  the  hammer  or  mallet.  This  will  cause  the 
heads  of  the  brads  to  make  corresponding  impressions  on 
both  blocks.  At  these  impressions,  bore  holes  one-half 
inch  deep.  The  diameter  of  the  hole  is  of  small  moment  ; 
for  patterns  of  this  size,  one -fourth  inch  is  about  right; 
the  larger  the  work,  the  larger  the  pins  should  be. 


SPECIAL  TYPES   OP   PATTERNS  79 

The  next  thing  will  be  to  make  the  pins,  for  which 
a  piece  about  ten  inches  long  will  be  found  the  best. 
Select  a  piece  that  is  straight  in  the  grain,  and  rip  to 
such  a  size  that  one  side  of  the  square  stick  equals  the 
diameter  of  the  hole,  plus  one-eighth  of  an  inch.  With 
the  jackplane  plane  this  into  an  octagonal  form.  Then, 
grasping  one  end  in  the  left  hand  and  laying  the  other 
end  on  the  bench,  with  the  block -plane  plane  off  the 
the  corners,  making  it  as  nearly  round  as  possible  for 
about  three  inches  of  its  length.  This  round  part  should 
be  made  to  fit  the  hole  exactly,  that  is,  at  the  extreme 
end.  With  knife  and  sandpaper,  or  file,  round  this  end 
to  an  approximately  parabolic  form.  Now  set  it  into  the 
hole  in  the  piece  into  which  the  pins  are  not  to  be  fas- 
tened, far  enough  so  that  it  exactly  fits  the  hole.  Make  a 
pencil  mark  part  way  around  it,  right  at  the  surface  of 
the  block.  Now  measure  the  depth  of  the  hole  into 
which  the  pin  is  to  be  fastened,  and  mark  this  distance 
along  the  pin  from  the  mark  previously  made.  This  is 
the  point  at  which  to  saw  the  pin  off.  Now,  if  this  pin  be 
driven  down  into  the  hole  clear  to  the  bottom,  the  first  mark 
will  come  even  with  the  parting  and  will  exactly  fit.  By 
means  of  these  pins,  the  two  parts,  after  being  separated, 
may  be  brought  together  again  in  exactly  the  same 
relative  position,  and  will  beheld  firmly  so  that  they  will 
not  slide  or  shift  sidewise  during  the  process  of  molding. 
They  should  be  loose  enough  so  that  the  pattern  will  fall 
apart  of  its  own  weight,  but  still  not  loose  enough  so  that 
there  is  any  perceptible  movement  sidewise.  When  both 
pins  are  in  place,  the  blocks  are  ready  to  be  fastened 
together.  There  are  three  ways  in  which  this  may  be 
done.  If  there  is  time  to  wait  for  glue  to  dry,  the  best 
way  is  to  put  glue  on  the  ends  of  each  piece  for  a  dis- 


80  WOOD    PATTERN    MAKING 

tance  of  about  one -half  inch,  and  clamp  them  together 
with  a  handscrew  or  other  clamp.  If  it  is  desired  not  to 
wait  for  the  glue,  then  a  screw  may  be  put  through  the 
ends,  fastening  them  together  in  that  way.  It  is  advis- 
able, for  convenience  in  turning,  to  use  a  short  screw, 
boring  a  hole  large  enough  to  receive  the  head  of  the 
screw.  For  a  piece  of  this  size  a  one  and  one -fourth 
inch  screw  may  be  used.  If  care  is  taken  to  have  one- 
half  the  length  of  the  screw  in  each  piece,  it  can  be  turned 
to  the  required  size  of  the  print,  out  to  the  extreme  end. 
The  third  method  is  to  clamp  them  together  with  "dogs," 
which  are  small  square  staples  made  for  the  purpose. 
When  the  pieces  are  thus  fastened  together,  they  are 
ready  to  be  placed  in  the  lathe  and  the  turning  proceeded 
with.  This  may  be  done  practically  in  the  same  way  as 
in  the  previous  example.  One  must  allow  for  draft,  and 
also  for  finish  on  the  faces  of  the  flanges,  making  these 
faces,  and  the  ends  of  the  prints  convex  as  shown  in 
Fig.  44. 

The  next  thing  will  be  the  core  box.  As  this  pattern 
requires  what  is  known  as  a  plain,  cylindrical,  horizontal 
core,  and  is  therefore  symmetrical,  only  a  half-box  is 
needed.  But  if  it  is  desired  to  reduce  the  cost  in  the 
foundry,  a  core  box  like  the  one  represented  by  Fig.  10, 
page  39,  in  the  chapter  on  cores,  would  be  used,  the 
core  being  made  complete  at  one  operation.  The  half- 
box  would  be  made  as  directed  for  the  straight  part  of  the 
core  box  in  the  last  example,  with  end  pieces,  as  repre- 
sented by  Fig.  45  If  a  whole  box  is  made,  then 
the  block  would  need  to  be  twice  as  long,  and  worked 
out  as  in  Figs.  38  and  39.  After  this  is  worked  out, 
it  should  be  cut  in  two  pieces  and  pinned  together  in 
the  same  way  as  was  done  with  the  two  pieces  for  the 


SPECIAL  TYPES  OF   PATTERNS  81 

pattern.  One  way  that  is  quite  practical  is  the  fol- 
lowing: After  cutting  the  pieces  the  correct  length, 
place  them  together  in  their  proper  relation  to  each  other; 
fasten  them  in  the  vise  in  a  vertical  position,  with  one  end 
above  the  bench  top,  and  bore  a  hole  of  the  size  required 
for  the  pin  clear  through  the  first  piece  and  about  half 
an  inch  into  the  other.  Now  by  putting  the  pin  through 
the  hole,  it  will  be  filled  and  make  an  accurate  and 
workmanlike  job.  If  brass  pins  are  used,  this  could  not 
be  done,  because  the  pin  would  not  fill  the  hole;  and  as 
the  pin  and  its  tube  are  of  a  different  size,  the  hole  could 
not  be  bored  with  the  same  bit.  The  inside  length  of 
this  core  box  should  be  about  one -eighth  of  an  inch 
shorter  than  the  total  length  of  the  pattern  and  prints,  so 
that  the  core  may  be  more  easily  set  into  the  mold. 


"Oliver"  Bandsaw 


CHAPTER  X. 


PLATE  WORK  AND  IRREGULAR  PARTING 


The  next  example  to  be  taken  up  is  typical  of  a  quite 
large  class  of  pattern  -  work, generally  known  as  plate  work. 
It  is  usually  comparatively  thin  in  cross -section  in  at  least 
one  direction.  This  class  of  work  includes  shafting, 
hangers  of  different  patterns,  some  kinds  of  small  pump 
standards,  and  any  kind  of  work  that  is  composed  of  two 
webs  running  into  or  crossing  each  other.  This  last  is 
illustrated  by  Fig.  46.  The  example  to  be  used  to 
demonstrate  the  methods  usually  followed  in  building 
patterns  of  this  type  is  represented  by  Figs.  46  and  47. 
In  order  to  make  the  best  pattern  for  durability  and  per- 
manence of  form,  the  foundation  should  be  built  of  three 
pieces,  as  shown  in  Fig.  47,  which  is  almost  self-explan- 
atory. Of  course,  this  part  of  the  pattern  could  be  built 
of  one  piece  of  board,  but  it  would  be  very  weak  through 
the  portion  marked  A.  By  building  it  as  represented, 
two  things  are  gained;  it  is  uniformly  strong  throughout, 
and  smaller  pieces  of  wood  may  be  used.  As  in  the  case 
of  all  other  patterns,  so  in  this,  it  should  be  first  deter- 
mined how  the  pattern  is  to  be  withdrawn  from  the  mold .  It 
I  will  soon  be  seen  that  the  best  way  will  be  to  have  the  face 
marked  B  (Fig.  46)  down  in  the  nowel ;  thus  there  will  be 
left  an  almost  flat  surface  for  the  molder's  parting,  which 
will  then  occur  along  line  C  D.  It  will,  of  course,  be  neces- 


84 


WOOD    PATTERN    MAKING 


sary  to  make  part  E  loose,  so  it  will  lift  with  the  cope: 
sand.  This  is  a  type  of  what  is  known  as  lOOSC  pieces 
molded  in  the  cope  and  drawn  therefrom  after  it  is  lifted 
Off  from  the  nowel,  or  lower  part  of  the  mold.  The 


FIG.  46. 

method  now  to  be  described  of  laying  out  and  building 
this  pattern,  may  be  used  in  building  any  pattern  of  this 


PLATE    WORK   AND    IRREGULAR    PARTING  85 

general  type ;  modifications  of  it  may  be  introduced  when 
needed. 

The  first  step  to  be  taken  in  making  this  pattern  is 
the  making  of  two  pieces  of  board  about  fifteen  inches  long, 
by  two  and  one -half  inches  wide,  and  five -eighths  inch 
thick,  and  one  piece  about  nine  inches  long,  four  inches 
wide,  and  five -eighths  inch  thick.  These  must  be 
planed  on  one  side  to  a  true  plane,  with  the  edges 
straight  and  at  right  angles  to  the  side ;  a  face  mark  should 
be  put  on  each  piece.  Now  the  two  long  pieces  should 
be  cut  to  shape,  so  as  to  make  a  good  joint  at  F,  care 
being  taken  that  the  two  lower  corners  are  far  enough 
apart  to  include  all  of  the  pattern  at  that  point.  Tack 
these  to  the  bench  or  laying-out  table  in  their  proper 
position  with  relation  to  each  other;  then  locate  points 
G  H,  and  lay  the  third  piece  on  the  others  with  its  edge 
at  these  points,  and  make  knife  marks  across  the  two 
pieces.  Now,  without  moving  the  third  piece,  make 
marks  on  it  with  the  point  of  the  knife  at  the  points  K, 
L,  M,  and  N;  then  finish  the  lay  ing -out,  and  cut  out 
gains  half  way  through  the  two  long  pieces.  Then  cut 
out  the  ends  of  the  short  piece  to  the  same  thickness, 
but  on  the  opposite  side ;  fit  them  together  and  glue  them 
and  put  them  in  clamps  till  dry.  While  this  is  drying,  a 
piece  of  board  about  fifteen  inches  long,  six  inches  wide, 
and  one -half  inch  thick,  can  be  gotten  out.  Out  of  this 
can  be  sawn  pieces  for  making  the  curved  pieces  that  are 
built  on  to  form  the  raised  portions  that  are  to  be  glued 
on  to  the  main  piece.  These  should  be  cut  from  the 
board  so  that  the  grain  of  the  wood  will  run  parallel  with 
a  chord  of  the  curve,  making  the  segment  not  to  exceed 
one -quarter  of  the  circumference  of  the  circle.  If  they 
are  made  longer  than  this,  there  will  be  too  much  end" 


86 


WOOD    PATTERN    MAKING 


grain.  The  straight  pieces  may  also  be  gotten  out  at  this 
time,  so  they  will  be  ready  when  wanted.  When  the 
glue  is  dry  on  the  three  pieces  that  together  form  an 
A-shaped  piece,  it  is  to  be  planed  on  both  sides  to  true 
planes  until  it  is  one-half  inch  thick.  It  is  now  ready  to 
have  the  lines  laid  out  on  it  as  shown  by  Fig.  47.  In 


FIG.  47. 


laying  out  these  dimensions,  the  shrink  rule  should  be 
used,  as  that  will  allow  for  the  shrinkage  of  the  metal  in 
the  casting.  After  these  are  all  laid  out,  it  may  be  sawn 


PLATE   WORK   AND   IRREGULAR    PARTING  87 

out  on  the  band  and  jig  saws.  In  doing  this  sawing,  it 
is  best  to  cut  just  outside  the  line,  so  that  in  filing  and 
finishing  the  edges,  the  marks  may  serve  as  a  guide.  It 
is  now  ready  to  have  the  pieces  set  on  to  form  the  pro- 
jecting webs,  which  may  be  cut  from  the  one -half  inch 
piece  already  mentioned.  It  will  be  best  to  commence  at 
the  top  of  the  pattern. 

The  first  will  be  a  solid  piece  extending  all  over  the 
upper  end  down  to  and  including  the  semi -circle  that 
joins  the  long  outside  webs.  After  this  the  other  cir- 
cular parts  may  be  cut  out  and  put  on.  Now  the  pieces  to 
form  the  feet  may  be  made  and  glued  in  place ;  then  the 
straight  pieces  should  be  nicely  fitted  to  these  and  glued 
in  place.  Now  a  piece  of  wood  may  be  gotten  out  to  form 
the  fillet  around  the  bearing  where  it  joins  the  main  part 
of  the  pattern.  This  should  be  about  three -eighths  inch 
thick,  and  should  be  large  enough  to  extend  three - 
eighths  inch  all  round  outside  the  bearing.  For  con- 
venience in  cutting  out  the  fillet,  it  is  best  to  let  the 
grain  of  the  wood  in  this  piece  run  parallel  with  the  out- 
side line  of  the  pattern  at  this  point.  A  piece  is  also 
needed  to  go  on  the  other  side  to  form  a  fillet  on  which 
to  pin  the  loose  piece.  (E  Fig.  46. )  Now  a  piece  to  form 
the  bearing  itself  may  be  made.  As  this  is  required  to 
be  more  than  a  half  circle,  it  will  be  best  to  make  it  with 
the  planes.  According  to  the  dimensions  given,  it  will 
need  to  be  of  the  following  finished  measurements :  about 
four  inches  long,  two  and  one -fourth  inches  wide,  and 
one  and  three -eighths  inches  thick.  It  should  be  planec1 
square  to  these  dimensions,  and  a  semi -circle  described 
on  each  end,  and  then  planed  and  sandpapered  down  to 
it.  A  piece  can  now  be  cut  from  this  just  two  inches 
long,  and  fastened  on  top  of  the  three -eighth  inch  fillet 


88  WOOD   PATTERN   MAKING 

piece.  Both  ends  of  this  piece  must  be  square,  so  it  will 
set  in  a  vertical  position  on  one  end,  and  so  the  core  print 
to  be  made  later  will  fit  well.  Apiece  of  this  is  required 
for  the  other  or  cope  side,  one  inch  long.  This,  how- 
ever, will  not  be  fastened  in  place  permanently,  but  will 
be  pinned  on  so  that  it  will  lift  with  the  cope 
sand  when  the  cope  is  lifted  off.  The  best 
way  to  do  this  is  to  place  it  in  a  correct  position 
and  drive  two  small  brads  through  it,  taking  care  not  to 
put  them  where  the  pin  holes  are  to  be  bored.  Now, 
with  brace  and  bit,  bore  two  holes  clear  through  it  and 
into  the  other  part  of  pattern  to  a  depth  of  about  one- 
half  inch.  A  one -fourth  inch  auger  bit  is  a  good  size  to 
use  for  this  purpose. 

Now  make*  pins  as  directed  for  use  in  the  parted 
pattern  on  page  78.     In  this  case  they  can  be  put  through 


and  fill  the  holes,  as  they  will  have  to  be  on  the  loose 
piece. 

The"  next  thing  will  be  to  make  the  core  prints. 
These  will  extend  the  whole  length  of  the  bearing,  and 
of  course  the  length  of  the  prints  besides,  and  as  this  is 
a  vertical  core,  will  project  one  inch  beyond  the  pattern 
oh  each  side.  To  make  these  prints  for  this  particular 
job,  take  a  piece  of  wood  about  seven  inches  long  and 
one  and  one -half  inches  square,  place  it  in  the  lathe 
and  turn  to  shape  and  dimensions  as  shown  by  Fig.  48. 
The  shaded  portion  will  be  cut  out  so  it  will  fit  down  on  to 


PLATE    WORK   AND    IRREGULAR    PARTING 


89 


the  pattern  already  made.  The  line  just  above  the  shaded 
part  is  the  point  to  cut  through  so  as  to  coincide  with  the 
pattern  parting. 

To  complete  this  example  a  core  box  will  be  needed, 
which  will  be  made  as  shown  at  Fig.  49.     The  process  is 


FIG.  49 

the  same  as  already  described,  except  as  to  the  pieces 
marked  X.  These  are  to  form  a  crease  or  groove  in  the 
core,  to  form  the  babbitt  pieces  on  the  casting  shown  at 
O,  Fig.  46.  These  are  simply  pieces  of  wood  one-eighth 
inch  thick,  of  a  size  equal  to  the  cross -section  of  the 
core  box,  and  with  a  semi -circle  cut  in  on  one  side,  whose 
diameter  is  one  inch,  that  is  the  size  of  the  shaft  the 
bearing  is  intended  to  carry.  In  building  the  box,  the 
pieces  must  be  nailed  in  between  the  body  of  the  box  and 
the  parts  forming  the  prints.  The  completed  box  is 
shown  at  Fig.  49. 

The  pattern  for  a  hook  lever  for  Corliss  valve  gear 
will  be  the  next  one  taken  up.  This  gives  a  good  exam- 
ple of  what  is  known  in  the  foundry  as  an  irregular  part- 


90 


WOOD    PATTERN    MAKING 


ing,  and  is  illustrated  in  the  chapter  on  molders'  joints 
by  Fig.  17,  the  molders'  parting  following  the  heavy 
dotted  line.  It  is  also  a  good  example  of  what  may  be 
called  a  built  up  solid,  One-plCCC  pattern,  meaning  that  the 
completed  pattern  has  no  parting.  This  is  typical  of  a 
very  large  class  of  patterns,  as  all  patterns  would  be 
made  one-piece  if  they  could  be  conveniently  molded  in 
that  shape.  Before  commencing  the  actual  work  on  this 
pattern,  notice  particularly  the  position  of  the  molders' 
parting  and  then  the  direction  of  the  required  draft.  The 
first  pieces  to  be  gotten  out  will  be  the  two  of  which  to 
make  the  arms,  each  about  four  and  one -half  inches 
wide,  ten  inches  long  and  three -fourths  inch  thick. 
These  should  be  planed  to  a  true  surface  on  both  sides 


FIG.  50. 


to  the  exact  thickness,  three -fourths  inch,    then   nailed 
together  so  their  center  lines  will  be  at  the  required  angle 


PLATE  WORK  AND  IRREGULAR  PARTING 


91 


of  105°.  On  one  surface  of  these  lay  out  the  shape 
accurately  as  indicated  by  the  drawing,  allowing  about 
one -sixteenth  inch  for  draft  around  the  central  boss. 
The  arms  may  nowlbe  sawn  out  on  the  band  saw,  leav- 
ing the  marks  as  a  guide  for  finishing  with  a  file.  The 
round  boss  or  disk  A  (Fig.  50)  may  now  be  made.  This 
should  be  sawn  out  about  four  and  one -fourth  inches  in 
diameter,  one  and  one -fourth  inch  plus  one -eighth  inch 
for  "finish"  in  thickness,  and  mounted  on  the  lathe  and 
turned  to  exact  dimensions,  which  are  four  inches  in  diam- 
eter at  B  and  four  and  one -sixteenth  inches  at  C,  Fig.  50 
(a) .  Another  boss  is  needed  at  D,  Fig.  50,  but  only  three- 
eighths-inch  thick.  These  may  now  be  nailed  in  place  on 


FiG.  50  (a). 

the  arms,  care  being  taken  as  to  the  side  on  which  each  is 
put,  as  the  position  of  these  pieces  will  determine 
whether  the  pattern  is  to  be  a  right  or  left  hand  lever. 


92  WOOD    PATTERN    MAKING 

This  can  be  easily  settled  by  comparing  the  work  already 
done  with  the  drawing.  A  screw  chuck  affords  a  good 
means  for  holding  these  pieces  in  the  lathe,  and  also  the 
stock  out  of  which  to  turn  the  four  bosses  required  for 
the  ends  of  the  arms.  These  four  may  all  be  turned  out 
of  one  piece  by  cutting  off  apiece  from  a  two -inch  plank 
about  two  inches  long,  measured  in  the  direction  of  the 
grain,  and  six  inches  long,  across  the  grain,  and  mount- 
ing it  in  the  lathe  so  that  the  grain  is  perpendicular  to 
the  axis  of  the  lathe.  This  is  plainly  shown  by  Fig.  50A. 
After  these  bosses  are  all  fastened  in  place  (they  should 
be  so  placed  that  the  grain  will  run  in  the  same  direction 
as  it  does  in  the  arms)  the  arms  may  be  shaped  or 
rounded  into  the  elliptical  form  indicated  at  L,,  Fig.  50(a) 
and  all  the  different  surfaces  blended  into  each  other  so  as 
to  make  one  general  even  surface.  The  central  hole  or 
bore  as  it  is  sometimes  called,  will  of  course  be  made 
with  a  dry  sand  core,  so  that  it  will  be  necessary  to  use 
coreprints  and  a  core  box.  This  being  a  vertical  core, 
the  shape  of  prints  and  core  box  will  be  the  same  as  for 
the  first  exercise,  Fig.  38  on  page  71. 


CHAPTER  XL 


PULLEY   PATTERNS 


The  next  kind  of  pattern -work  to  be  considered  is 
the  making  of  patterns  of  the  general  shape  of  Fig.  32, 
sometimes  called  annular  patterns.  The  example  used 
for  the  purpose  of  explaining  how  such  work  is  done  is 
the  pattern  for  an  eight-inch  pulley  with  a  three-inch 


FIG.  53 

face.  The  technical  description  for  shop  use  is  written 
like  this:  Pulley  S^xS",  hub  2%",  four  arms,  rim  %6" 
thick.  The  "g""  means  the  outside  diameter  of  the 


94  WOOD    PATTERN    MAKING 

pulley;  the  "3""  the  width  of  face;  "2^""  the  diam- 
eter of  the  hub  or  central  boss,  through  which  the  shaft 
runs;  and  "4  arms",  the  radial  arms  or  spokes  that 
connect  this  central  boss  with  the  rim  of  pulley ;  the 
"3/i6"  rim"  is  the  thickness  of  the  rim  at  its  outer  edge. 
The  finished  pulley  is  represented  by  Fig.  53. 

The  first  step  in  the  case  of  this  pattern  as  of  all 
others,  is  to  determine  how  it  is  to  be  molded.  As  to 
mold  it  from  a  one-piece  pattern  would  be  quite  difficult, 
it  is  best  to  make  a  parted  pattern,  the  parting  being 
made  on  a  central  plane  running  through  the  center  of 
the  arms;  this  means  that  two  halves  will  be  made.  The 
first  thing  to  do  is  to  prepare  a  chuck  about  9  inches  or 
nine  and  one-half  inches  in  diameter  and  about  one  inch 
thick,  and  face  it  off  true.  On  this  chuck  build  up  a 
ring  or  hollow  cylinder  high  enough  so  that  both  halves 
may  be  cut  from  it.  If  enough  is  built  for  both  halves, 
it  will  need  to  be  three  inches,  equal  to  the  width  of  pul- 
ley face,  plus  one  inch  for  cutting  off,  making  in  all  four 
inches  in  height.  This  is  to  be  built  of  straight -grained 
white  pine  about  seven -eighths  inch  thick;  therefore  it 
will  take  five  thicknesses  for  the  required  height.  These 
pieces  will  be  cut  into  segments  or  cants  of  such  length 
that  four  will  complete  the  circle.  They  must  be  cut  so 
that  the  grain  of  the  wood  is  parallel  to  the  chord  of  the 
Curve.  These  will  be  cut  on  the  bandsaw  or  jigsaw,  and 
made  large  enough  so  that  the  ring  may  be  turned  and 
still  allow  for  draft  and  finish.  As  one-sixteenth  inch 
is  to  be  allowed  for  draft  and  one -eighth  inch  for  finish, 
and  as  the  finished  pattern  will  need  to  be  eight 
and  three -eighths  inches  in  diameter  at  the  center, 
the  rough  built-up  ring  should  be  about  eight 
and  three -fourths  inches  in  diameter.  For  a  guide  in 


PUIXEY   PATTERNS  95 

building,  make  a  pencil  mark  on  the  chuck  while  it 
revolves  in  the  lathe  so  that  the  circle  thus  made  will  foe 
of  the  required  diameter.  To  mark  out  the  segments, 
proceed  as  follows:  Set  the  dividers  at  the  radius 
required  (4#")  and  describe  an  arc  tangent  to  the  edge 
farthest  from  you  of  the  board  from  which  it  is  proposed 
to  cut  the  cants.  Set  the  dividers  to  three  and  one -half 
inches,  and  describe  another  arc ;  this  will  leave  the  cants 
three -fourth  inch  wide;  lay  a  framing  square 
on  the  board  at  an  angle  of  45°  with  its  edge, 
with  the  heel  exactly  over  the  center  from  which 
the  arcs  were  struck;  and  at  the  point  where 
the  sides  of  the  square  cross  the  arcs,  make  marks.  This 
will  give  the  length  of  the  required  segment  and  at  the 
same  time  give  the  radial  line  which  is  the  correct  line  for 
cutting  the  cants.  If  the  board  is  too  long  to  carry  to 
the  bandsaw  conveniently,  cut  off  with  the  handsaw  a 
piece  just  long  enough  for  the  segment.  Saw  out  this 
one  segment,  using  it  as  a  pattern  with  which  to  mark 
out  all  the  other  nineteen  cants  required.  This  pattern 
segment  should  be  cut  out  so  that  it  will  be  a  little  too 
long;  then  the  others,  when  marked  out  by  it,  may  be  cut 
to  the  mark  and  still  be  long  enough  to  allow  for  fitting,  as 
the  joints  must  be  exact.  Now  saw  out  four  more  and 
then  proceed  to  fasten  them  on  the  chuck.  The  others 
may  be  sawn  out  while  the  glue  is  drying.  Now  a  trim- 
mer or  shoot  board  will  be  needed  on  which  to  shoot  or 
plane  the  ends  of  the  pieces.  The  shoot  board  and  the 
method  of  its  use  are  shown  in  Fig.  54.  The  trimmer  is 
a  more  complicated  machine  and  is  represented  by  half- 
tone on  page  97.  Plane  or  trim  both  ends  of  one  of  the 
segments  and  drive  a  two -inch  brad  into  it  at  each  end, 
from  the  top  side  almost  through  it ;  put  some  glue  on 


96 


WOOD    PATTERN   MAKING 


the  ends  and  on  the  under  side,  and  place  it  on  the 
chuck  just  inside  the  circle  already  made,  driving  the 
brads  down  until  the  heads  protrude  just  far  enough  so 
that  they  may  later  be  withdrawn  with  the  claw  hammer. 
Now  fit  another  segment  up  to  this  one,  being  sure  that 
it  makes  a  good  joint,  especially  on  the  inside  of  the  ring. 


FIG.  54. 

For  if  a  poor  joint  is  made,  the  small  triangular  pieces 
formed  in  cutting  the  segments  will  be  torn  out  by  the 
chisel  during  the  process  of  turning.  The  second  piece 
may  now  be  glued  into  place,  being  sure  as  before  to  put 
glue  on  both  ends  and  also  on  the  end  of  the  piece  that  is 
in  place.  Thus  the  ends  of  the  pieces  are  glued  twice, 
which  is  very  necessary  if  a  strong  joint  is  wanted.  This 
is  called  sizing  the  joint.  If  it  is  not  done,  the  first  coat 
of  glue  will  be  absorbed  by  the  wood  and  the  joint  will 
be  weak.  This  course  may  be  followed  until  the  first 
ring  or  layer  of  segments  is  complete,  when  it  should  be 


Oliver"    Trimmers 


PULLEY   PATTERNS  99 


allowed  to  dry.  After  the  glue  is  dry,  the  brads  may  be 
pulled  out  and  the  chuck  put  in  the  lathe  and  the  ring 
faced  off,  making  it  true  in  both  directions.  The  next 
layer  may  now  be  put  on  in  the  same  way.  The  ends  of 
the  cants  should  be  placed  about  in  the  center  of  those 
in  the  lower  layer,  so  as  to  break  joints. 

The  above  is  the  method  usually  followed  in  making 
this  form  of  pattern  when  the  cross -section  of  the  ring  is 
small,  that  is,  of  three-fourths  inch,  or  less.  If  the  ring 
is  to  be  one  inch  or  more  thick,  it  is  best  to  use  hand- 
screws  to  hold  the  different  layers  down  until  the  glue  is 
dry.  If  simply  a  ring  is  wanted,  that  is  one  inch  or 
more  in  thickness,  and  we  are  sure  there  is  no  cutting  to 
be  done  on  it  in  the  future,  then  the  brads  may  be  driven 
clear  in  and  left  in  the  work,  except  in  the  first  layer. 
This  will,  of  course,  obviate  the  waiting  for  the  glue  to 
dry,  so  that  a  ring  may  be  built  up  very  rapidly.  Zinc 
nails  or  wooden  pegs  may  also  be  used  in  this  class  of 
work,  but  if  a  good  quality  of  glue  is  used,  they  are  not 
necessary,  except  in  very  thin  work.  The  work  is  now 
ready  for  the  lathe.  It  is  advisable  before  turning  it  to 
glue  up  the  stuff  for  the  arms  and  hub ;  then  we  need  not 
wait  for  the  glue  to  dry,  as  it  will  dry  by  the  time  the 
rim  is  turned,  unless  this  is  done  much  more  quickly  than 
it  usually  is. 

There  are  two  general  ways  of  building  up  the 
spider,  as  it  is  sometimes  called,  of  a  pulley;  which  is  the 
better  way  is  determined  by  the  size,  number  of  arms, 
and  some  other  things.  One  way  is  what  is  known  as 
checking  the  arms  together,  and  then  gluing  the  boss  on 
afterwards.  This  is  a  good  way,  if  care  is  taken  so  that 
they  fit  exactly.  If  they  are  made  too  tight,  however, 
the  ends  are  likely  to  be  bent  out  of  the  correct  position. 


100 


WOOD    PATTERN    MAKING 


This  method,  of  course,  cannot  be  used  for  spiders  hav- 
ing an  odd  number  of  arms.  A  better  way  for  most  work 
is  to  miter  the  arms  together.  The  only  objection  to  this 
method  is  that  it  is  comparatively  weak.  But  this  defect 
is  easily  overcome;  for,  if  there  is  no  hub  or  boss 
required,  a  recess  may  be  turned  into  the  arms  after  they 
are  glued  together,  and  a  piece  of  haidwood,  or  metal, 
set  in  and  a  screw  put  into  each  arm,  as  shown  in  Fig.  55. 


FIG.  55: 

If  a  hub  is  wanted,  and  it  usually  is,  this  will  give  the 
required  strength.  This  method  may  be  used  for  spiders 
of  any  number  of  arms. 

To  make  the  spider,  then,  for  this  pattern  and  in  the 
last  mentioned  way,  the  first  thing  to  do  is  to  get  out 
eight  pieces,  four  and  one -half  inches  long,  one  and 
three -fourth  inches  wide,  and  about  five -sixteenths  inch 
thick;  cut  one  end  of  each  piece  so  as  to  make  an  angle 


PATTERNS  101 

of  90°  at  an  angle  of  135°  to  each  edge.  Now  saw  out 
on  the  band  or  jig  saw,  two  disks  about  three  inches  in 
diameter,  and  one  and  one-fourth  inches  thick,  and  glue 
four  of  the  thin  pieces  on  to  each  disk,  with  the  point  of 
the  90°  angle  directly  in  the  center.  The  best  way  to  do 
this  is  to  start  three  one -inch  brads,  one  in  each  corner 
of  the  triangle;  put  on  some  glue,  lay  the  piece  in  place 
and  drive  the  nails  down,  leaving  the  heads  projecting  so 
the  brads  may  be  afterwards  withdrawn  with  the  claw 
hammer  or  pincers.  Now  these  may  be  set  aside  to 
allow  the  glue  to  dry.  While  these  are  drying,  the  rim 
may  be  turned  to  size  and  cut  off.  The  chuck,  with  the 
built-up  rim  on  it,  may  now  be  put  in  the  lathe  and  the 
rim  turned  to  size.  The  extreme  outside  diameter  should 
be  eight  and  three -eighths  inches.  This  is  for  the  central 
plane  through  the  hollow  cylinder.  At  the  ends  of  the 
cylinder,  that  is  at  the  point  where  it  is  glued  to  the 
chuck  and  the  opposite  or  outer  end,  the  diameter  should 
be  eight  and  one -fourth  inches.  These  measurements 
must  be  made  with  the  shrink  rule.  Before  starting  the 
lathe,  see  to  it  that  it  will  not  run  too  fast.  The  work 
to  be  turned  should  run  at  a  surface  velocity  of  from 
1200  to  1400  ft.  per  minute  for  pine  wood.  This  will  also 
give  very  satisfactory  results  on  all  ordinary  soft  wood. 
If  the  wood  is  unduly  soft,  a  higher  speed  may  be 
required.  It  may  run  much  faster  than  this  with  safety, 
but  it  is  best  to  keep  the  speed  down  as  low  as  may  be  and 
still  do  good  work.  The  work  in  hand  should  be  run  com  - 
paratively  slow  at  first,  so  as  to  turn  off  any  inequali- 
ties of  building,  both  on  the  inside  and  outside ;  as  the 
work  becomes  cylindrical  in  form,  a  higher  rate  of  speed 
may  be  used.  The  inside  had  better  be  turned  first,  and 
a  diamond -pointed  tool  will  be  the  best  to  rough  it  out 


102  WOOD    PATTERN    MAKING 

with,  using  a  regular  scraper  for  the  finishing.  The 
size  inside  at  the  center  will  be  seven  and  three -eighths 
inches  diameter;  at  the  two  ends,  seven  and  five-eighths 
inches  diameter.  Finish  the  outer  end  back  to  a  short 
distance  beyond  the  center;  in  other  words,  back  far 
enough  to  make  a  little  more  than  one -half  of  the  rim, 
which  will  be  one  and  five-eighths  inches. 

When  it  has  been  turned  as  suggested,  it  is  ready  to 
be  cut  off.  L,ocate  the  cutting-off  point  by  holding  a 
pencil  exactly  one  and  five -eighth  inches  from  the  edge, 
while  it  is  revolving;  this  will  make  a  mark  at  the 
proper  point.  Now  take  a  parting  tool,  and  cut  into  the 
work  just  outside  this  mark  and  almost  through,  leaving 
a  very  thin  section  which  may  be  cut  through  with  a 
knife.  It  is  not  good  practice  to  cut  clear  through,  for 
the  work  may  fall  on  the  floor,  receiving  more  damage 
than  can  be  repaired  in  the  time  it  takes  to  cut  it  off 
with  a  knife.  If  the  work  has  been  done  correctly,  we 
have  one -half  of  the  required  rim.  As  for  the  other 
half,  it  is  already  turned  to  size  at  the  outer  end,  and  all 
that  needs  to  be  done  is  to  turn  the  rest  of  it  to  the  size 
and  shape  of  the  first  one. 

Before  being  cut  off,  both  of  these  halves  should  be 
thoroughly  sandpapered,  first  with  coarse,  and  then  with 
finer;  No.  2  for  the  coarse,  and  No.  1  for  the  fine  are  the 
best  numbers  to  use.  After  they  are  taken  from  the  lathe 
it  is  well  to  give  the  rims  a  good  coat  of  black  varnish, 
as  it  will  prevent,  to  a  degree,  their  tendency  to  warp  out 
of  shape. 

The  spiders  are  probably  dry  by  this  time,  so  that 
work  can  be  resumed  on  them.  First,  they  must  be 
planed  to  a  perfectly  plane  surface  on  what  will  be  the 
parting  in  the  completed  pattern,  so  that  they  will  exactly 


PULLEY  PATTERNS  103 

fit  each  other.  Now  take  the  chuck  you  have  just  used 
for  turning  the  rim,  and  face  it  off  to  a  surface  that  is  a 
very  little  concave;  then  while  the  lathe  is  revolving, 
make  a  circle  about  the  size  of  the  disk  in  the  spider.  Set 
one -half  of  the  spider  on  the  chuck  so  that  the  disk 
coincides  with  this  circle,  and  drive  a  brad  in  two 
of  the  arms  and  into  the  chuck.  Before  doing  this, 
though,  it  is  well  to  select  two  one -inch  screws,  and 
with  brace  and  drill  bore  a  hole  through  two  of  the  arms 
just  the  size  to  fit  the  screws;  these  holes  should  be 
countersunk  for  the  head  of  the  screw,  so  that  they  will 
set  in  below  the  surface  of  the  arms,  to  permit  of  their 
being  turned  to  the  proper  surface.  Now  the  half  spider 
may  be  set  as  suggested,  and  the  brads  driven  far  enough 
so  that  they  will  hold  the  spider  while  the  screws  are 
being  turned  in.  With  the  scraping  tool  face  off  the 
whole  thing  in  order  to  true  up  the  faces  so  that  a  mark 
can  be  made,  and  make  a  circle  on  the  face  of  the  arms 
equal  in  diameter  to  the  outside  of  the  rim  on  the  center 
of  the  pattern.  You  will  notice  that  this  is  where  the 
arms  will  finally  be  joined  to  the  rim.  Inside 
of  this  circle  the  arms  will  be  cut  down  to  the 
required  thickness  ( one -fourth  inch ),  and  to  the  required 
thickness  at  the  hub  (five -sixteenths  inch).  The  sur- 
face of  the  arms  should  be  a  straight  line  between  these 
two  points.  The  hub  can  now  be  turned  to  size,  (two  and 
one-fourth  inches),  in  diameter.  There  must  be  a  fillet 
in  the  angle  between  the  arms  and  hub  of  about  one- 
fourth  inch  radius.  In  the  center  of  the  hub  turn  a  hole 
about  three -fourths  inch  in  diameter,  and  one -half  inch 
deep,  to  receive  a  core  print.  Sandpaper  the  hub  and  also 
the  arms  for  a  short  distance  from  the  hub,  taking  care  not 
to  get  your  fingers  caught  by  the  arms  as  they  swing 


104  WOOD   PATTERN    MAKING 

around.  On  the  arms  should  be  marked  a  circle  whose 
diameter  is  the  same  as  the  inside  of  the  rim  at  the  center 
of  the  pattern.  This  circle  will  serve  two  purposes,  as  it 
furnishes  a  place  to  space  around  to  locate  the  center  of 
the  arms,  and  also  locates  the  point  of  tangency  between 
the  arm  and  the  fillet  that  must  be  formed  on  the  arm. 
Another  circle  should  be  made  around  the  hub ;  this  may 
be  about  three  inches  in  diameter;  the  exact  size  is  not 
material.  Now  this  half  may  be  removed  and  the  other 
half  put  on  and  treated  in  the  same  way,  except  that  the 
two  circles  last  mentioned  need  not  be  made.  The  next 
thing  to  do  is  to  lay  out  the  lines  for  the  shape  of  the 
arms.  First  make  a  mark  that  is  exactly  radial  along  the 
whole  length  of  one  arm,  and  as  near  the  center  as  can 
be.  Starting  from  this  line,  by  the  use  of  the  dividers 
divide  the  circle  near  the  outer  end  of  the  arms  into  four 
spaces ;  the  points  thus  formed  will  locate  the  center  line 
of  all  the  arms.  Divide  the  circle  that  is  near  the  hub  in 
the  same  way,  starting  from  the  same  line.  Set  the 
dividers  to  one -half  the  width  of  arms  at  these  points, 
and  make  marks  on  each  side  of  these  points;  these 
marks  will  locate  the  sides  of  the  arms ;  now  with  a  short 
straight-edge,  join  the  marks  by  a  line  along  both  sides 
of  the  arms.  It  is  required  to  have  fillets  at  the  intersec- 
tion of  the  last  made  lines  and  the  outer  circle,  which 
may  be  marked  out  by  setting  the  dividers  to  the 
required  radius  (one-fourth  inch),  and  describing  an  arc 
that  shall  be  tangent  to  the  straight  line  and  the  circle. 
Fillets  are  also  required  at  the  point  where  the  arm  joins 
the  hub;  these  should  be  tangent  to  a  circle  about  one- 
half  inch  out- from  the  hub  and  to  both  arms;  the  radius 
to  be  such  that  one  arc  shall  touch  all  three  points.  The 
sides  of  the  part  of  the  arms  that  are  set  into  the  rim  are 


PULLEY   PATTERNS  105 

now  to  be  located  and  marked.  This  is  done  by  making 
a  mark  parallel  with  the  center  line  of  the  arm ;  it  should 
start  from  the  point  of  tangency  of  the  fillet  arc  and  the 
circle  representing  the  inside  of  the  rim,  and  should 
extend  to  the  end  of  the  arm.  All  of  the  above 
marks  should  be  on  the  same  side  as  the  hub. 

Next  put  the  two  half  spiders  together  so  that  the  two 
hubs  shall  be  exactly  over  each  other,  or  exactly  con- 
centric, and  fasten  them  temporarily  by  driving  a  small 
brad  through  two  of  the  arms.  These  brads  had  better 
be  put  as  near  the  end  of  the  arms  as  may  be.  With  a 
brace  and  five -sixteenths  inch  auger -bit  bore  holes 
through  two  of  the  arms  for  pattern  pins.  These  pins 
should  be  located  so  that  they  will  not  be  symmetrical  with 
the  center  of  the  pattern;  that  is,  one  should  be  about 
three -fourths  inch  further  from  the  center  than  the  other. 
These  are  now  ready  to  be  sawn  out,  which  can  be  done 
either  on  the  band  saw,  jigsaw,  or  with  the  keyhole  saw, 
sawing  out  one  half  at  a  time.  This  will  be  easy  to  do 
in  the  case  of  the  first  half,  but  in  that  of  the  other  not  so 
easy;  for,  as  the  second  has  been  marked  from  the  first 
one,  the  marks  will  be  on  the  flat  side,  so  that  the  hub 
will  come  on  the  under  side.  To  do  the  work  more 
easily,  take  a  small  block  of  wood  with  one  dimension 
equal  to  the  distance  that  the  hub  projects  above  the  arms, 
and  set  it  under  the  end  of  each  arm  as  it  is  being  sawn. 
It  will  be  safer  to  drive  a  brad  through  the  arm  into  the 
block,  so  that  in  moving  it  around  on  the  table  of  the  saw 
machine  it  cannot  get  out  of  place.  If  it  is  preferred, 
both  halves  may  be  sawn  at  once;  but  if  this  is  done,  the 
pattern  pins  should  first  be  put  in  so  as  to  make  sure  that 
the  two  halves  will  be  exactly  alike,  and  will  set  over 
each  other  just  right.  After  these  are  sawn  out  they  must 


106  WOOD   PATTERN   MAKING 

be  filed  nicely  to  the  lines;  then  give  them  the  required 
elliptical  form  by  rounding  off  the  corners  and  blending 
in  all  the  curves  with  each  other  so  that  a  uniform  sur- 
face is  formed. 

The  rims  and  spiders  are  now  ready  to  be  put 
together.  Lay  one  of  the  half  rims  on  the  bench  with 
the  side  up  that  will  be  the  center  of  the  pattern,  and  lay 
on  one  of  the  half  spiders.  If  everything  has  been  done 
as  directed,  they  will  be  self-centering  because  of  the 
extra  thickness  that  was  left  on  the  end  of  the  arms  when 
turning  them.  If  this  has  not  been  done,  they  may  be 
centered  by  the  use  of  inside  calipers,  measuring  from 
the  side  of  the  rim  into  the  hub  on  three  or  more  sides. 
This  should  be  done  very  carefully,  for  if  the  hub  is  not 
in  the  center  it  will  not  look  very  well  when  the  hole  is 
bored  for  the  shaft,  and  of  course  it  will  not  be  balanced. 
When  the  spider  has  been  correctly  located,  make  a  mark 
with  a  knife  on  the  edge  of  the  rim  on  both  sides  of  each 
arm ;  before  taking  the  spider  off  be  sure  to  mark  one  of 
the  arms  and  the  place  where  it  belongs,  so  that  it  can 
be  put  back  into  the  same  position.  Now  set  a  gauge  to 
the  thickness  of  the  ends  of  the  arms,  and  gauge  a  line 
parallel  with  the  edge  of  the  rim  between  the  marks  on 
the  edge  for  the  recess  for  the  arms.  Now  saw  down  to 
this  gauge  mark  and  remove  the  wood,  making  a  nice 
clean  gain  exactly  to  lines.  Now  the  arms  maybe  glued 
and  nailed  in  place. 

The  other  half  should  be  treated  in  the  same  way. 
Before  marking  recesses,  lay  them  together  and  notice  if 
everything  is  coming  concentric ;  if  not,  you  can  change 
the  position  of  the  second  spider  slightly,  so  as  to  make 
it  right.  After  getting  them  together  in  this  way,  the 
extra  length  of  the  arms  may  be  sawn  off  and  the  parts 


PULLEY   PATTERNS  107 

smoothed  up.  Two  core  prints  will  be  wanted  for  the 
hubs;  these,  of  course,  will  be  tapered  because  the  core 
will  be  vertical.  A  coat  of  varnish  should  be  put  on  the 
spider,  the  rim  having  been  varnished  before.  The 
whole  thing  is  now  ready  to  be  finished.  First,  fill  up 
with  beeswax  any  small  holes  and  any  other  defects  in 
wood  or  work.  A  fillet  is  needed  on  the  inside  of  the 
rim,  on  the  side  of  each  arm  of  both  halves.  This  can 
also  be  of  wax,  put  in  with  a  filleting  tool  of  one -half  inch 
diameter.  Further  directions  for  finishing  will  be  found 
on  page  141.  To  make  this  job  complete,  a  core  box  will 
be  needed,  the  same  as  one  described  on  page  71,  (Fig. 
38),  except  as  to  dimensions. 


CHAPTER  XII. 


PATTERNS   FOR   CAST   GEARS 


The  next  class  of  work  to  be  taken  up  requires  the 
greatest  amount  of  care  and  attention  on  the  part  of  the 
pattern-maker,  as  in  order  to  obtain  the  best  results  his 
work  must  be  correct  in  all  its  details.  The  class  of  work 
referred  to  is  the  making  of  gear  patterns,  especially 
patterns  for  what  are  known  as  Cast  gears.  By  this  is 
meant,  gears  of  which  the  teeth  are  cast  to  the  required 
size  and  shape,  without  being  cut.  There  are  two  gen- 
eral ways  of  manufacturing  gears. 

One  way  is  to  cast  what  is  known  as  a  gear  blank, 
which  is  turned  to  size  and  the  teeth  cut  from  the  solid 
metal.  This  is  the  method  usually  employed  for  small 
work,  and  for  gears  that  are  required  to  run  very 
smoothly.  They  are  spoken  of  as  a  class,  as  CUt  gears. 

But  if  the  gears  are  large  and  of  coarse  pitch,  the 
patterns  are  made  with  the  teeth  of  the  approximate  size 
of  the  finished  teeth.  That  is,  each  surface  of  each  tooth 
on  the  pattern  is  treated  the  same  as  a  finished  surface  on 
any  pattern,  i.  e.,  about  one-eighth  inch  is  allowed  for 
finish  or  machining.  After  the  casting  is  made,  the  teeth  are 
cut  on  the  gear  cutter  just  as  the  full  blank  would  be  for  a 
small  gear.  Casting  them  in  this  way,  of  course,  saves 
an  immense  amount  of  cutting,  thereby  economizing  on 
time  and  the  wear  of  cutters.  When,  however,  only  one 


PATTERNS    FOR    CAST    GEARS 


109 


gear  of  a  particular  size  and  pitch  is  wanted,  it  is  not 
profitable  to  do  this ;  in  this  case  the  pattern  is  cut  to  the 
exact  size  of  the  teeth;  as  in  a  large  class  called  "cast 
gears." 

It  best  serves  the  purpose  of  this  volume  to  illus- 
trate some  general  principles  in  regard  to  making  gear 
patterns  that  can  be  applied  by  the  student  to  any  par- 


FIG.  56. 

ticular  case.  Consequently,  in  preference  to  a  gear  of 
any  specific  size,  gears  of  the  last  mentioned  kind  will 
be  considered. 

The  part  to  be  considered  first  is  the  rim  or  periph  • 
ery  of  the  wheel,  to  which  the  teeth  are  fastened.     There 


110 


WOOD   PATTERN    MAKING 


are  several  ways  that  this  maybe  built  up;  the  difference 
is  mainly  in  regard  to  the  method  of  holding  it  in  the 
lathe  while  being  turned.  The  actual  building  should  be 
done  as  explained  for  the  pulley  rim,  that  is,  with  seg- 
mental  pieces  of  wood  of  the  required  size  and  thickness. 
As  the  cross  section  is  of  somewhat  different  shape,  the 
segments  will  of  course  vary  also.  If  the  gear  is  to  be 
large  enough  so  that  both  sides  can  be  gotten  at  at  the 
same  time  while  running  in  the  lathe,  the  best  way  is 
to  build  up  the  rim  on  what  may  be  called  a  three -armed 
chuck.  This  is  made  as  illustrated  by  Fig.  56. 
The  width  of  the  arms  will  be  determined  by  the 


FIG.  56A. 

size  of  the  gear.  For  gears  up  to  two  feet  in  diameter, 
pieces  seven -eighths  inch  thick  by  three  inches  wide, 
will  be  heavy  enough.  The  length  of  the  arm  will  be 
equal  to  the  radius  of  the  rim  only.  These  arms  are  to 


PATTERNS    FOR    CAST  GEARS  111 

be  mitered  and  fastened  to  a  disk  a  little  larger  than  the 
face  plate  that  it  is  proposed  to  use ;  the  fastening  is  to  be 
done  with  screws,  as  indicated.  The  face  plate  should 
be  put  on,  and  the  chuck  put  in  the  lathe;  then  the  face 
of  the  arms,  for  a  distance  somewhat  more  than  the  width 
of  the  stock  for  the  rim  should  be  faced -off  true. 

It  is  now  ready  to  have  the  segments  glued  on  for  the 
rim.  As  will  be  seen,  the  first  row  of  segments  must  be 
made  up  of  three  pieces  and  jointed  in  the  center  of  each 
arm.  After  this  is  glued  in  place,  the  rest  of  the  struc- 
ture may  be  made  up  of  shorter  ones,  in  fact,  of  any 
length  desired.  The  building  process  should  be  con- 
tinued in  this  way  until  completed,  leaving  the  arms  of 
the  chuck  as  near  the  center  of  the  rim  as  possible. 

It  is  now  ready  to  be  turned  to  size  and  shape,  which 
should  be  done  with  scraping  tools ;  it  should  be  tested 
for  shape  with  a  templet.  It  is  not  well  to  cut  the  arms 
down  too  thin  until  the  teeth  blocks  have  all  been  glued 
on  and  turned  to  size.  In  other  words,  all  the  turning  to 
be  done  should  be  completed  before  cutting  into  the 
chuck  arms  very  much ;  otherwise  the  rim  may  spring. 
When  all  the  other  turning  is  done,  the  arms  may  be  cut 
almost  through  with  very  little  danger.  Of  course  the 
more  nearly  through  they  are  cut,  the  less  work  will  have 
to  be  done  by  hand  after  it  is  taken  from  the  lathe ;  this 
should  be  left,  however,  until  the  tooth  blocks  are 
glued  on  and  the  turning  all  done. 

The  next  thing  to  do  is  to  mark  out  the  spaces  in 
which  to  fasten  the  tooth  blocks.  If  the  pitch  of  the  gear 
is  not  more  than  one  inch,  these  blocks  may  be  made  of 
such  a  size  that,  allowing  one  for  each  tooth,  they  will 
form  a  complete  circumference  around  the  rim.  The 
grain  of  the  blocks  must  be  perpendicular  to  the  side  of 


112 


WOOD    PATTERN    MAKING 


PATTERNS    FOR   CAST   GEARS 


113 


the  gear,  or  in  other  words,  parallel  with  the  axis  of  the 
wheel.  They  should  be  made  of  good,  clear,  straight  - 
grained  wood,  thoroughly  seasoned. 

There  are  several  ways  of  putting  these  blocks  on 
the  rim.  Three  ways  will  be  explained  that  will  include 
all  the  practical  ideas  and  principles  of  this  branch  of 
pattern -making.  In  all  three,  the  rim  at  its  present 
stage  will  be  laid  out  in  the  same  way,  that  is,  spaced 
into  as  many  spaces  as  it  is  required  to  have  teeth  in 
the  wheel.  The  three  ways  spoken  of  will  be  more 
clearly  understood  by  referring  to  Fig.  57. 

The  method  shown  by  the  tooth  A  is  what  may  be 
called  the  cheap  way.  In  this  case  the  teeth  are  formed 


FIG.  59. 


FIG.  58. 


before  being  fastened  in  place.  They  may  be  formed  in 
two  ways.  One  is  to  plane  up  strips  of  wood  to  the 
desired  shape,  and  then  cut  them  off  to  the  required 


114  WOOD    PATTERN   MAKING 

length.  A  better  way  is  to  make  a  box  as  illustrated  by 
Fig.  58,  each  block  being  cut  to  exact  length  and 
held  in  place  by  a  screw,  as  shown.  Fig.  59  shows 
the  method  of  getting  the  shape  of  this  box.  In  using 
this  box,  care  must  be  taken  not  to  cut  away  any  part  of 
it  in  planing  the  tooth  to  shape.  To  locate  a  tooth  on  the 
rim,  set  the  dividers  to  exactly  half  its  thickness;  place 
one  leg  on  the  center  marks  already  made,  and  with  the 
other  leg  make  a  mark  on  each  side ;  these  marks  will 
indicate  the  position  for  the  sides  of  the  tooth  block.  Of 
course  these  marks  must  be  squared  across  the  face  of  the 
rim  so  that  the  teeth  may  set  square.  When  gluing 
them  on  use  a  try -square  to  test  them;  do  not  depend 
wholly  on  the  marks  for  this.  The  above  method  does 
very  well  for  a  job  where  only  one  or  two  wheels  are 
wanted,  and  for  cases  where  it  is  not  desired  to  go  to  the 
expense  of  a  good  job  of  pattern -making.  The  second 
way  is  to  glue  all  the  blocks  on  the  rim,  lay  them  out  in 
that  position,  and  then  cut  to  the  lines.  This  makes  a 
good  job  when  properly  done,  but  it  is  rather  incon- 
venient to  cut  the  teeth,  especially  if  the  face  of  the  gear 
is  very  wide.  There  is  another  way  that  is  known  as  the 
dove -tailing  method,  so  named  because  each  tooth  is 
glued  to  a  thin  block  let  in  to  the  rim.  One  dis- 
advantage of  this  way  is,  that  if  the  dovetails  are  driven 
a  little  too  tight,  it  is  very  likely  that  the  rim  will  be 
sprung,  and  the  resulting  casting  will  not  be  round. 
About  the  only  advantage  claimed  for  this  method  is  that 
one  or  more  of  the  teeth  may  be  removed  and  used  by  the 
molder  for  patching  up  a  broken  mold ;  but  this  can  be 
attained  in  another  way.  The  method  of  dovetailing  is 
illustrated  at  B.  Fig.  57.  It  is  a  very  expensive  method, 
and  is  now  almost  obsolete. 


PATTERNS   FOR    CAST   GEARS  115 

The  best  way  to  fasten  and  form  the  teeth  on  gear 
patterns  is  the  one  shown  in  the  center  of  Fig.  57.  It 
should  be  used  on  all  standard  patterns.  This  method 
was  first  published  by  P.  G.  Dingey  in  the  American 
Machinist.  Before  entering  into  the  details  of  this  way, 
some  of  its  advantages  should  be  noticed.  It  does  away 
entirely  with  the  objection  mentioned  in  connection  with 
the  dovetailing  method,  viz.,  springing  the  rim  by 
driving  the  dovetails;  and  at  the  same  time  it 
permits  that  one  or  more  of  the  teeth  be  removed  by  the 
molder,  if  necessary.  Another  great  advantage  gained 
is  that  the  fillets  are  made  in  solid  wood,  thus  producing 
a  much  smoother  pattern  and  casting.  None  of  the 
other  methods  shown  have  this  advantage.  In  the  dove- 
tailing method  a  very  thin  edge  must  necessarily  be  left 
at  this  point.  In  the  first  method  described  a  wax  fillet 
would  generally  be  used,  which  in  the  course  of  frequent 
use  is  very  liable  to  be  loosened  by  the  shrinking  and 
swelling  of  the  wood,  leaving  the  pattern  rough  just 
where  it  ought  to  be  the  smoothest.  Another  advantage 
in  the  method  under  consideration  is  that  one -half  of 
the  teeth  being  fastened  on  with  screws,  each  alternate 
tooth  may  be  removed,  thus  making  room  for  working 
those  glued  on. 

In  this  method  the  first  thing  to  be  done,  after  build- 
ing up  the  rim,  is  to  turn  the  rim  down  about  one -half 
inch  smaller  in  diameter  than  the  diameter  of  the  whole 
depth  circle,  or  to  the  point  lettered  D  in  Fig.  57. 
Then,  of  course,  the  tooth  blocks  will  have  to  be  made 
larger  by  that  amount  than  the  size  of  the  tooth  proper. 
After  the  rim  is  turned  to  size  it  should  be  spaced  as 
previously  suggested.  This  should  be  done  accurately 
so  that  each  tooth  may  come  in  the  center  of  each  block. 


116  WOOD   PATTERN   MAKING 

One  set  of  lines  will  do  if  the  pitch  of  the  gear  is  not  too 
coarse  to  allow  the  stock  of  which  the  tooth  blocks  are 
to  be  made,  to  fill  the  spaces.  Otherwise,  two  sets  of 
lines  will  be  required,  and  pieces  must  be  glued  in 
between  the  blocks,  as  represented  atE,  Fig.  57.  When 
the  blocks  are  ready  and  the  rim  is  marked  out,  one  of 
the  blocks  may  be  glued  in  place.  Do  not  get  too  much 
glue  on,  as  it  will  be  likely  to  make  trouble  in  putting 
on  the  next  block,  for  this  is  to  be  fastened  on  without 
any  glue.  With  a  brace,  and  a  bit,  of  the  proper  size  for 
the  screws  to  be  used,  bore  two  holes  through  the  rim  as 
near  the  center  of  the  space  for  the  next  block  as  may 
be ;  counter  -  sink  them  on  the  inside  of  the  rim  to  receive 
the  heads  of  the  screws.  Hold  the  second  block  in  posi- 
tion, and  with  a  brad  or  small  drill  mark  on  the  block  the 
places  for  the  screws,  and  bore  them  with  a  suitable  sized 
drill.  Now,  holding  the  block  in  position  again,  insert  the 
screws,  driving  them  in  until  the  heads  are  slightly  below 
the  surface  of  the  rim.  This  process  should  be  carried 
on  until  the  blocks  are  all  fastened  on.  Be  very  careful 
not  to  glue  the  blocks  together  for  at  least  half  an  inch 
from  the  surface  of  the  rim,  and  also  not  to  glue  the 
blocks  having  screws,  to  the  rim,  or  it  will  make  trouble 
later  on.  In  getting  out  the  blocks  for  any  of  the  last 
three  methods  described,  they  should  be  made  about 
one -eighth  inch  longer  than  finished  size,  and  then 
turned  off  in  the  lathe  so  as  to  make  a  good  smooth  sur- 
face on  which  to  lay  out  the  pitch  circle,  base  circle  and 
tooth  curves,  and  also  on  which  the  spacing  of  the  teeth 
may  be  done.  When  the  blocks  have  been  glued  on  and 
allowed  to  dry,  the  whole  of  the  work  should  be  put  in  the 
lathe,  the  ends  of  the  teeth  blocks  turned  off  even  with  the 
edge  of  the  rim,  and  the  face  turned  down  to  the 


PATTERNS    FOR   CAST   GEARS 


117 


required  size.  After  this  is  done,  a  coat  of  yellow  var- 
nish may  be  put  on  the  parts  that  are  to  form  the  teeth. 
This  makes  a  much  better  surface  on  which  to  make  lines 
than  does  the  bare  wood. 


\ 


A  Pitch  circle 

B  Addendum  circle 

C  Base  circle 

D  Whole  depth  circle 

f  Working  depth  circle 

f  Radius  =  l-4th  of  pitch  circle 

Q  Radius  =  l-4th  of  pitch  radius 

n  Center  of  gear 


•  =7-15th  of  Pitch 
b  =8-15th  of  Pitch 
C  =5-15th  of  Pitch 
d  =6-15th  of  Pitch 

Kadius  of  e  =  l-6th  of  f 


Fig.  5  6 


H 


FIG.  60 

There  are  several  ways  of  laying:  out  the  tooth  curves 
on  the  pattern.  First,  however,  it  must  be  decided  what 
method  is  to  be  used  for  developing  these  tooth  curves. 


118  "WOOD   PATTERN    MAKING 

These  may  be  developed  by  the  Epicycloidal  curve,  by 
the  Odontograph,  or  by  the  Involute  curve.  It  is  not 
intended  in  this  volume  to  enter  into  a  discussion  of  the 
merits  or  demerits  of  any  one  one  of  these  systems,  or 
even  to  explain  them,  but  simply  to  call  attention  to  them 
and  to  indicate  one  or  two  ways  of  applying  them  to  the 
pattern.  Theoretically,  the  use  of  the  Odontograph  is 
probably  the  best,  especially  for  large  work;  but  for 
comparatively  small  work  a  careful  use  of  the  dividers 
will  give  as  good  results,  and  if  only  single  curve  or 
involutes  are  desired,  the  use  of  the  dividers  afford  the 
quickest  way.  In  deciding  what  method  of  development 
is  to  be  used,  one  or  two  further  facts  should  be  consid- 
ered. The  involute  form  will  give  uniform  angular  velocity 
if  the  distance  between  the  centers  of  any  two  gears  does 
not  remain  uniform,  as,  for  instance,  in  the  feed  rolls  of 
the  common  rotary  knife  planer.  Other  forms  of  teeth 
will  not  do  this.  Again,  if  dividers  are  used  for  marking 
out  these  forms  on  the  pattern,  the  single  curve  is  much 
more  quickly  laid  out.  The  single  curve  method  is  fully 
illustrated  by  Fig.  60,  and  is  what  may  be  called  a  simple 
shop  method.  It  can  be  used  to  advantage  when  the  data 
supplied  by  the  draftsman  to  the  pattern-maker  does  not 
indicate  any  particular  method. 

The  first  thing  that  needs  to  be  known  is  the  pitch 
and  number  of  teeth.  Of  course  this  was  learned  before 
building  up  the  pattern ;  so  all  that  needs  now  to  be  done 
is  to  apply  this  knowledge  to  the  work.  The  first  line  to 
put  on  the  work  will  be  the  pitch  circle ;  divide  this  into 
as  many  equal  parts  as  there  are  to  be  teeth  in  the  gear  ; 
this  is  for  the  purpose  of  locating  the  center  of  each 
tooth.  In  doing  this  it  will  be  found  advantageous  to 
commence  at  one  side  of  the  center  of  tooth  block  for  the 


PATTERNS    FOR   CAST  GEARS  119 

trial  spacing;  then  having  the  dividers  set  to  the  cor- 
rect distance,  start  from  the  center  of  a  block.  Then 
there  will  not  be  several  points  to  confuse  one  in  fixing 
the  correct  one  for  the  center  of  the  tooth,  as  is  likely  to 
be  the  case  if  the  centers  of  the  blocks  are  used  for  the 
trial  division.  Now  set  the  dividers  to  one -half  of  the 
tooth  thickness  as  derived  from  Fig.  60  at  (a)  ;and  mark  a 
point,  one  each  side  of  the  teeth  centers:  this  will  locate 
the  sides  of  the  teeth.  The  base  circle  (C,  Fig.  60) 
should  now  be  put  on,  its  diameter  is  found  as  indicated 
by  arcs  F  and  G.  Now  setting  the  dividers  to  one- 
fourth  of  the  radius  of  gear,  as  at  G,  Fig.  60,  proceed  to 
describe  tooth  curves,  being  very  careful  that  the  arc 
runs  through  the  points  located  for  the  side  of  the  tooth 
on  the  pitch  circle.  The  centers  for  these  tooth  curves 
are  all  on  the  base  circle.  At  the  points  where  these  tooth 
curves  intersect  the  addendum  circle  (B,  Fig.  60),  lines 
must  be  drawn  square  across  the  face  of  the  pattern,  and 
the  opposite  side  laid  out  with  corresponding  curves,  each 
curve  starting  from  the  point  where  these  squared  lines 
intersect  the  corner.  Arcs  for  fillets  at  the  base  of  all  the 
teeth  will  now  be  put  in,  which  will  complete  the  laying 
out  of  the  teeth. 

The  next  work  to  be  done  is  to  saw  out  on  a  band- 
saw,  if  one  is  available,  the  wood  between  the  teeth  to 
form  the  spaces.  This  should  be  done  very  carefully; 
leave  one -half  of  the  marks  on  the  work  so  that  there 
will  remain  very  little  to  be  done  with  chisel  and  gouge. 
The  fillets  will  have  to  be  made  with  a  small  gouge,  as 
the  ordinary  bandsaw  is  too  wide  to  turn  in  so  small  a 
curve  as  is  required  in  small  or  medium  sized  work.  If  a 
gear  of  coarse  pitch  is  being  made,  there  would  be  little  dif- 
ficulty in  making  the  saw  do  most  of  that  work  also.  If 


120  WOOD   PATTERN    MAKING 

the  teeth  were  put  on  the  rim  as  suggested  for  standard 
work, — that  is,  if  only  each  alternate  tooth  is  glued  on, 
and  the  others  fastened  with  screws, — then  by  taking  out 
those  with  screws,  the  finishing  can  be  done  very  easily; 
the  teeth  so  taken  out  should  be  numbered  and  cor- 
responding numbers  pat  on  the  spaces,  so  that  they  may 
be  replaced  in  their  proper  places  after  being  finished. 
The  temporary  arms  of  the  chuck  may  now  be  cut 
through,  thus  finishing  up  the  work  of  making  the  rim 
and  teeth.  The  shape  of  this  rim  may  be  more  clearly 
seen  by  referring  to  Fig.  56A.  The  way  of  attaching 
the  arms  also  is  shown  in  this  figure,  as  well  as  in 
Fig.  57. 

The  next  process  is  to  make  the  spider,  or  arms. 
This  may  be  done  as  described  in  the  making  of  the 
8 -inch  pulley  pattern,  except  that  in  this  case  they 
must  be  made  of  one  thickness  and  fastened  in  as  shown 
in  Fig.  57. 

As  these  arms  are  made  of  one  thickness,  one 
side  will  be  turned  up  after  the  face  plate  is  removed. 
This  may  be  done  in  a  cup  chuck  shown  by  Fig.  50,  in 
the  chapter  on  Turning.  In  this  case  the  cup  will  be 
turned  out  to  fit  the  hub  already  turned.  The  arms  will 
be  made  of  the  same  elliptical  shape  and  in  the  same  way 
as  described  in  the  case  of  the  eight-inch  pulley,  Fig.  53. 

BEVEL  GEAR  PATTERNS. 

Before  taking  up  the  construction  of  bevel  gear  pat- 
terns, it  will  be  well  to  say  something  about  the  lines 
required  for  laying  them  out.  The  first  thing  is  to  make 
two  lines  at  right  angles  to  each  other,  to  represent  the 
center  line  of  the  shafts  on  which  the  bevel  gears  are  to 
be  fastened.  Bevel  gears  may  be  made  to  run  shafts  at 


PATTERNS   FOR  CAST    GEARS 


121 


FIG.  61. 


122 


WOOD   PATTERN   MAKING 


other  angles  than  right  angles;  if  this  is  required,  the 
first  two  lines  laid  down  must  be  drawn  to  this  angle. 
The  next  step  is  to  determine  the  size  and  the  ratio  of  the 
pair  of  bevel  gears  to  be  made.  The  pitch  diameter  of  a 
bevel  gear  is  always  measured  at  the  large  end.  The 
pitch  of  the  teeth  is  also  measured  and  calculated  for 
this  end.  Having  determined  on  the  size  of  the  gear, 
set  the  dividers  to  the  pitch  radius  of  the  gear  and  prick 
off  this,  equidistant  from  line  A  B,  in  Fig.  61A,  which 
will  give  the  pitch  diameter.  Now  proceed  by  laying 
down  the  other  lines  in  Fig.  61  A.  Notice  that  the  teeth 
are  not  developed  on  the  pitch  circle,  but  on  a  projected 


FIG.  62. 

circle,  the  center  of  which  is  obtained  by  producing  the 
line  that  forms  the  end  of  the  teeth  back  until  it  inter- 
sects the  center  line  of  the  gear  at  H ;  the  small  end  is 
treated  in  the  same  way,  which  locates  the  center  for 


PATTERNS   FOR   CAST  GEARS 


123 


that  end  at  I.  The  dimensions  of  tooth  elements  may 
be  obtained  from  Fig.  60.  The  drawing  makes  it  clear 
as  to  how  a  bevel  gear  should  be  laid  out. 

The  building  of  the  pattern  may  now  be  considered. 
The  first  thing  to  do  is  to  select  a  chuck  of  proper  size, 
if  we  have  one,  or  make  one  if  we  have  not.  A  chuck 
for  this  purpose  may  be  built  as  shown  by  Fig.  62  ;  or  63, 


FIG.  63. 

if  very  large.  The  rim  at  A  may  be  left  off  if  thought 
best;  but  its  presence  is  an  advantage  if  it  becomes 
necessary  to  use  handscrews  for  holding  the  material  on 
the  chuck  during  the  process  of  gluing,  for  the  hand- 
screws  may  all  be  set  to  the  same  size,  and  so  more 
quickly  applied;  this  is  quite  an  advantage,  because  the 
glue  drys  very  quickly.  The  chuck  will  need  to  be  faced  off 


124  WOOD    PATTERN   MAKING 

to  a  true  surface,  and  some  fairly  thick  paper  glued  on  the 
part  where  the  segments  for  the  rim  are  to  be  fastened 
on.  With  this  exception,  the  process  of  building  this 
rim  will  be  the  same  as  for  the  eight -inch  pulley.  The 
lay  ing -out  and  the  sawing  of  the  cants  will  also  be  the 
same,  except  that  each  layer  will  have  to  be  described  with 
different  radii.  The  necessity  for  this  will  be  readily  seen 
by  consulting  Fig.  61B,  which  shows  the  rim  as  it  will 
appear  after  being  built  on  to  the  chuck,  and  before  it  is 
turned.  When  there  has  been  enough  segments  built  on, 
and  the  glue  has  dried,  it  is  ready  to  be  turned  to  shape,  as 
shown  by  Fig.  61B;  in  turning  it,  get  around  into  the 
work  at  point  P  as  far  as  possible. 

It  is  now  ready  to  be  taken  off  the  chuck,  which 
can  very  readily  be  done  by  introducing  a  chisel  between 
the  work  and  the  chuck,  and  driving  it  lightly  at  several 
places  around  the  circumference.  This  will  cause  the 
paper  that  is  glued  between  the  work  and  chuck  to  split, 
allowing  the  work  to  come  off,  without  any  damage  to 
either.  The  rim  must  now  be  mounted  on  the  chuck, 
with  the  opposite  side  out.  The  best  way  to  locate  it  on 
the  chuck  so  that  it  will  be  concentric  with  the  lathe 
spindle  (as  it  must  be  in  order  that  the  inside  and  out- 
side may  be  concentric),  is  to  turn  a  small  V-shaped 
groove  into  the  chuck  that  will  exactly  fit  the  corner  of 
the  rim  at  the  point  marked  R,  Fig.  5 1C.  The  work 
must  be  fastened  to  the  chuck  this  time  with  screws 
put  through  the  chuck.  To  do  this,  bore  holes 
through  the  chuck,  at  the  bottom  of  the  V- groove  just 
made,  of  a  suitable  size  for  the  screws  selected.  The 
number  of  screws  to  be  used  will,  of  course,  be  deter- 
mined by  the  size  of  the  work ;  from  four  to  six  will  be 
enough  for  work  up  to  three  feet  in  diameter.  Now  take 


PATTERNS    FOR   CAST    GEARS  125 

the  chuck  off  the  lathe;  and,  having  laid  the  rim  on  the 
bench  with  its  proper  side  up,  lay  the  chuck  on  it  and 
drive  the  screws  through  the  chuck  into  the  rim.  It  is 
now  ready  for  the  lathe  again,  and  may  be  turned  to  the 
size  and  shape  indicated  at  points  S,  Fig.  61C;  turn  it 
small  enough  so  the  tooth  blocks  maybe  put  on  as  indi- 
cated at  K,  Fig.  61F,  and  more  plainly  shown  in  Fig.  57 
at  C  C.  The  arms  may  now  be  made,  and  mitered 
together  in  the  center,  with  a  piece  on  each  side  for 
strength;  the  same  pieces  also  serve  as  fillets,  as  indi- 
cated at  B,  Fig.  61D.  The  arms  should  be  set  into  the 
rims  as  shown  at  D,  Fig.  61D,  before  the  work  is  taken 
from  the  chuck.  The  vertical  arms  C  C,  with  the  cen- 
tral hub  E  must  be  left  loose  so  it  will  lift  with  the  cope. 
These  will  be  built  together  as  shown  by  Fig.  61E. 


CHAPTER  XIII. 

PIPE  FITTINGS 

Another  large  and  interesting  class  of  patterns  are 
those  required  in  the  manufacture  of  cast-iron  pipe 
fittings,  two  types  of  which  will  now  be  taken  up.  The 
castings  are  what  is  known  as  a  bend,  shown  at  Fig.  64, 


FIG.  64. 

and  an  elbow,  shown  at  Fig.  72.  The  larger  part  of  the 
pattern  work  can  be  done  on  the  lathe  for  both  of  these 
examples. 

The  pipe  bend  will  be  taken  up  first.  The  first 
thing  is  to  prepare  a  chuck  large  enough  in  diameter; 
turn  its  face  perfectly  flat,  and  glue  paper  all  over  it. 

The  stock  required,  as  illustrated  by  Fig.  65,  must 
be  large  enough  to  contain  the  size  of  pattern  it  is  pro- 
posed to  build,  indicated  by  the  circle  on  the  figure.  This 


PIPE   FITTINGS 


127 


should  be  put  on  the  chuck  in  two  pieces,  as  shown  in 
the  cut;  each  half  has  one  side  and  one  edge  planed 
straight  and  at  right  angles  to  each  other,  as  the  edges 
are  to  form  the  joint.  These  must  be  so  placed  on  the 


FIG.  65. 

lathe  that  the  joint  shall  be  exactly  on  the  center  of  the 
lathe.  The  best  way  to  do  this  has  already  been  explained 
in  connection  with  core  box  ends,  page  75.  They  are 
now  to  be  turned  to  the  shape  indicated  by  Figs.  66.  The 


PIG.  66. 

next  parts  to  be  made  are  those  shown  at  Figs.  67  and 
68.     These  must  be  made  in  halves  and  turned.      Before 


128 


WOOD    PATTERN    MAKING 


they  are  turned,  a  pattern  pin  should  be  put  into  each, 
so  that  it  will  not  have  to  be  done  after  the  pattern  is 
completed.  It  is  always  best  to  put  in  these  pins  before 
the  turning  is  done.  After  the  pieces  are  turned,  the 
parts  should  be  fitted  together  as  shown  at  Fig.  69.  The 


FIG.  67.  FIG.  68.  FIG.  69. 

part  marked  (d)  should  be  made  square,  as  shown  by 
E,Fig.  68.  Of  course,  both  halves  are  to  be  made  in  the 
same  way.  The  core  box  for  this  pattern  is  shown  at 


FIG.  70.  FIG.  71. 

Fig.  70.     The  circular  part  (d)  can  be  made  on  the  lathe; 
the   way  is  clearly   shown    at  Fig.    71.       The  grooves 


PIPE   FITTINGS 


129 


marked  (b)  may  be  made  in  one  piece  of  lumber,  and 
made,  of  course,  with  the  core  box  plane.  If  it  is  desired 
to  make  this  very  strong,  a  piece  of  board  is  nailed  on 
the  bottom,  as  indicated  at  (c). 

As  elbows  are  usually  cast  in  pairs  to  save  work  in 


FIG.  73.  FIG.  72. 

the  foundry,  the  pattern  must  be  made  double.  The 
economy  resulting  is  great,  as  it  will  take  but  very  little 
more  of  the  molder's  time  to  make  the  mold  for  both  than 
for  one.  Besides  the  core  can  be  more  easily  set  and  held 


130 


WOOD    PATTERN   MAKING 


in  place  if  two  are  made  in  the  one  mold.     If  only  one  is 
made,  a  chaplet  would  be  needed  to  hold  the  core;  or 
else  very  long  prints  would  have  to  be  put  on  the  pattern, 
either  of  which  would  increase  the  work  of  the  molder. 
The  pattern  for  the  elbow  is  a  little  more  complicated 


FIG.  74. 

than  for  the  bend,  though  the  work  is  quite  similar  in 
character  to  that  of  the  last  pattern.  It  is  made  as  fol- 
lows :  A  ring,  as  shown  at  Fig.  73,  is  first  turned,  with  its 
cross  section  as  indicated  at  (a).  The  best  way  to  make 
this  is  to  get  out  four  pieces  with  the  grain  as  indicated 


FIG.  75. 

in  the  figure;  that  is,  the  chord  of  the  curve  should  be 
parallel  with  the  grain  of  the  wood.  Fit  them  together 
very  accurately,  and  glue  them  to  a  chuck  (but  not  to 


PIPE;  FITTINGS 


131 


each  other)  that  has  been  previously  covered  with  paper, 
and  turn  them  to  the  required  shape.  A  solid  piece  may 
be  used  and  cut  into  the  required  number  of  pieces  after 
being  turned, but  this  method  is  not  as  good.  In  mount- 
ing these  pieces  on  the  chuck,  care  should  be  taken  to  see 
that  the  point  where  they  meet  is  exactly  on  the  center 
of  the  lathe.  Now  two  pieces  are  required  like  Fig.  74. 
These  will  be  made  in  halves  and  turned.  Both  will  be 


FIG.  76. 

alike,  except  that  on  one  the  shape  at  A  will  be  left  the 
full  size  and  of  a  length  to  equal  A  in  Fig.  75.  The  one 
made  like  the  figure  will  be  cut  in  two,  the  parts  B  and 
C  squared  as  at  E,  Fig.  69;  it  is  fitted  into  the  first  piece 
as  shown  at  B  and  C,  Fig.  75. 

The  core  box  to  go  with  this  pattern  is  shown  at 
Fig.  76.  The  circular  parts  A  and  B  can,  of  course,  be 
made  on  the  lathe  in  the  same  way  as  for  the  core  box 
shown  at  Fig.  70. 


CHAPTER  XIV. 


MISCELLANEOUS  EXAMPLES 


Fig.  78  shows  a  good  method  of  building  patterns 
that  are  flat,  square,  or  rectangular,  and  of  comparatively 
thin  cross  section.  The  casting  required  is  shown  by 
Fig.  77.  It  is  a  common  form  of  steam  chest  cover.  In 


FIG.  77. 

building  the  pattern,  the  central  part  is  made  up  of  nar- 
row strips  set  into  a  groove  in  the  outside  pieces ;  these 
are  mitered  together  and  tongues  driven  into  grooves  as 
shown  by  dotted  lines  at  A,  Fig.  78.  The  diagonal  ribs 
made  and  halved  together  and  then  cut  to  the  shape 


MISCELLANEOUS   EXAMPLES 


133 


shown.  They  should  be  left  loose  and  pinned  in  place 
with  pattern  pins,  so  that  the  molder  may  take  them  off 
in  order  to  lay  the  pattern  flat  on  the  molding  board  dur- 
ing the  first  operation  in  molding.  This  is  necessary,  as 
in  order  to  have  the  side  B  good  and  sound,  it  must  be 
cast  with  that  side  down ;  then  the  ribs  will  come  in  the 
cope. 


FIG.  78. 


SKELETON  PATTERNS 

The  term  "skeleton  patterns"  embraces  a  large  variety 
of  patterns;  it  refers  to  those  that  are  made  of  a  combina- 
tion of  wood  and  sand;  that  is,  both  wood  and  sand  are 
used  to  form  the  complete  pattern.  The  pattern-maker 
constructs  the  required  woodwork,  and  the  molder  makes 
the  rest  of  the  pattern  with  sand.  The  sand  commonly 
used  for  this  class  of  work  is  called  loam. 

One  example  of  this  class  of  patterns  is  shown  by 
Fig.  79.  It  is  a  skeleton  pattern  of  a  pipe  bend,  from 
which  only  one  or  two  castings  are  wanted.  The  drawings 
give  a  good  idea  of  the  general  make-up  of  the  pattern. 


134 


WOOD    PATTERN    MAKING 


The  core  and  method  of  making  it  are  shown  at  Fig.  80. 
The  parts  the  pattern-maker  would  have  to  make  in  order 
that  the  core -maker  could  produce  this  core,  are  the 
core  board,  as  it  is  called,  indicated  by  (b)  and  the 


FIG.  79. 

strickle  shown  at  (c)  in  Fig.  80.  The  core  board  is  simply 
a  piece  of  board  planed  up  true  on  both  sides,  and  cut  to 


FIG.  80. 

the  correct  shape.     Its  side  (d)  is  cut  in  such  a  way  that 
when  the  strickle  is  set  at  right  angles  to  it  and  slid  along 


MISCELLANEOUS   EXAMPLES  135 

its  length,  it  will  give  the  desired  size  and  shape  to  the 
core.  When  the  molder  uses  this  apparatus,  he  first  lays 
this  prepared  core  board  on  an  iron  plate,  and  clamps  or 
fastens  it  down  so  it  cannot  move.  He  piles  on  some 
sand  and  then  slides  the  strickle  along  so  that  the  point 
(E)  remains  in  contact  with  edge  (d),  taking  care  to 
keep  it  perpendicular  to  the  straight  part,  and  to  keep 
the  cutting  edge  exactly  radial  in  passing  along  the 
curved  part.  If  there  is  any  point  on  the  sand  that  the 
strickle  does  not  touch,  more  sand  is  put  on  and  the 
strickle  again  passed  over  it.  This  process  is  continued 
until  a  good  smooth  surface  is  produced.  The  core 
board  is  now  removed,  and  the  plate  with  the  complete 
half  core  on  it  set  into  the  core  oven  to  be  baked.  To 
make  the  other  half,  the  core  board  is  turned  over  and 
the  process  repeated.  These  two  halves  are  baked,  and, 
when  hard,  are  pasted  together,  so  forming  the  complete 
core.  The  making  of  the  pattern  is  carried  out  in  a  very 
similar  way,  but  requires  more  work  on  the  part  of  the 
pattern-maker.  The  first  thing  is  to  prepare  two  boards 
of  suitable  thickness  for  the  job;  this  is  determined  by 
the  size  of  the  pattern  to  be  made.  One  of  these  boards 
is  shown  at  (a)  Fig.  79.  They  will  be  sawn  out  to  the 
shape  of  the  pipe  on  its  axial  line,  including  the  core 
prints. 

These  boards  are  pinned  together  the  same  as  would 
be  done  if  a  complete  wooden  pattern  was  to  be  made. 
The  flanges  (f  f)  are  also  to  be  cut  out  so  that  they  will 
fit  over  the  board  at  the  correct  points.  The  semicircular 
pieces  (dd)  are  also  cut  out  and  fastened  on  at  equal 
distances,  and  also  for  the  core  prints  (c  c).  Two 
strickles  will  be  needed,  similar  to  the  one  used  for  mak- 
ing the  core,  Fig.  80  (c),  one  for  the  body  of  the  pat- 


136  WOOD    PATTERN   MAKING 

tern,  and  one  for  the  prints.  The  molder  completes  the 
pattern  by  laying  down  one  of  these  boards  on  the  bench, 
with  the  pieces  all  fastened  in  place,  puts  on  sand,  filling 
up  the  spaces,  and  then  passes  the  strickle  over  it,  thus 
making  a  smooth  surface  the  same  as  for  the  core.  The 
other  half  is  made  the  same  way.  When  the  pattern  is 
complete  the  molder  scatters  parting  sand  all  over  it  so  it 
will  leave  the  mold  freely. 

Another  class  of  skeleton  patterns  is  illustrated  by 
Fig.  81.     It  represents  a  pattern  for  a  curved  cast-iron 


FIG.  81. 

plate,  over  which  a  blacksmith  or  boiler -maker  may  bend 
or  form  a  plate  of  wrought  iron  or  steel.  Instead  of  mak- 
ing a  complete  pattern,  which  would  be  a  slow  and 
expensive  process,  a  frame  is  made  as  shown,  and  halved 
together  at  the  corners.  The  rest  of  the  pattern  will  be 
made  by  the  molder,  with  the  strickle,  shown  at  A  in  the 
figure.  Flat  plates  of  large  area  may  be  made  in  this 


MISCELLANEOUS   EXAMPLES 


137 


way,  that  is,  with  the  open  frame  and  strickles,  thereby 
saving  lumber  and  also  a  large  amount  of  pattern 
work.  A  pattern  of  this  kind  may  be  molded  by  first 
bedding  the  frame  in  the  nowel,  or  if  too  large  for  that, 
in  the  floor.  Then  fill  the  inside  with  sand,  and  strike  it 
off  even  with  the  top;  put  on  parting  sand  and  then 
ram  up  the  cope.  Lift  off  and  set  to  one  side.  With  a 
strickle  cut  like  A,  Fig.  81,  with  shoulder  B  the  same 
depth  as  the  thickness  of  the  plate,  cut  out  the  sand  to 
that  depth.  Now  take  out  the  frame  or  pattern,  and  there 
is  left  a  cavity  in  the  sand  of  the  size  and  thickness  of 
the  required  casting. 

GLUING  FEATHER -EDGE  BOARD 

In  building  some  large  patterns  it  becomes  necessary 
to  glue  on  what  may  be  called  a  feather -edged  piece 
of  wood,  in  order  to  make  a  shape  something  like  Fig.  82. 


FIG.  82. 

This   cannot  well    be   made  with    solid   wood   on 
account  of  the  difficulty  of  guiding  a  rebate  plane  along 


138  WOOD    PATTERN   MAKING 

the  obtuse  angle,  without  the  corner  of  the  iron  cutting 
into  the  other  side.  The  best  way  of  overcoming  this 
difficulty  is  to  use  the  method  as  shown  at  Fig.  82.  But 
this  introduces  another  problem.  How  can  the  feather- 
edge  be  glued  on  and  still  be  smooth,  without  a  sub- 
sequent planing?  Of  course  the  trouble  comes  from  the 
fact  that  a  thin  piece  of  wood  on  being  made  wet  with 
glue,  will,  unless  held  in  some  way,  warp  and  curl  all 
out  of  shape  while  drying.  A  way  of  overcoming  this 
difficulty  will  now  be  be  described.  After  having  pre- 
pared both  pieces  to  the  shape  indicated  in  the  figure, 
get  out  a  strip  of  wood  about  one -half  inch  by  one  inch, 
and  long  enough  to  extend  the  whole  length  of  the 
piece  to  be  glued ;  drive  a  number  of  brads  through  it 
about  six  inches  apart.  This  strip  must  exactly  fit  the  whole 
length.  Now  prepare  a  piece  or  pieces  of  good  paper  about 
one  and  a  half  to  two  inches  wide,  and  long  enough  to 
extend  the  whole  length.  Apply  the  glue  to  the  feather- 
edge  piece,  put  it  in  place,  and  tack  it  with  a  brad  or 
two  so  that  it  will  not  slip  around  out  of  place.  Then 
lay  the  paper  on  top  of  the  thin  feather -edge  of  the  piece 
being  glued  on,  and  lay  on  the  strip  of  wood  so  that  one 
edge  comes  exactly  along  and  even  with  the  thin  edge; 
then  drive  the  brads  down,  which  will  pulldown  the  thin 
edge  into  place.  Examine  the  feather -edge  to  see  that 
it  is  down  tight  to  the  other  piece.  If  any  spots  are  found 
that  are  not  in  contact,  put  in  another  nail  at  that  place; 
if  this  does  not  bring  it  down  to  place,  drive  a  sliver  of 
wood  under  the  strip  and  on  top  of  the  paper.  The  paper 
is  employed  in  this  case  to  prevent  the  strip  from  sticking 
to  the  work,  if  by  chance  some  glue  should  get  on  to  the 
upper  side  of  the  thin  edge.  Moreover,  if  the  edge  is 
very  thin,  the  glue  is  very  likely  to  ooze  through  the 


MISCELLANEOUS   EXAMPLES  139 

pores  of  the  wood  and  thus  glue  the  strip  to  the  work, 
and  when  it  was  taken  off,  it  would  tear  up  some  of  the 
wood  and  make  it  rough.  By  interposing  the  paper, 
this  is  prevented. 

The  work  should  now  be  allowed  to  stand  for  several 
hours,  or  until  the  glue  is  thoroughly  dry.  If  the  strip 
be  now  removed,  it  will  be  found  that  the  feather -edge 
has  become  practically  one  piece  with  the  other,  an,d  all 
that  is  needed  to  finish  the  job  is  to  sandpaper  the 
surface. 

LARGE  LATHE  CHUCKS 

The  method  of  building  a  chuck  shown  at  Fig. 
62,  on  page  122,  is  very  good  for  one  of  twelve  to 
twenty  inches  in  diameter;  but  larger  ones  should  be 
built  as  illustrated  by  Fig.  63,  on  page  123. 
Of  course  the  size  will  determine  the  number  of  arms 
required ;  for  chucks  up  to  four  feet  in  diameter,  four 
arms  of  two  inches  by  six  inches  in  cross  section  would 
be  suitable ;  if  larger  than  that,  it  would  be  preferable  to 
use  more  arms,  so  that  the  segmental  pieces  joining  the 
arms  need  not  be  so  longer  wide.  In  building  all  these 
chucks,  each  piece  of  corresponding  shape  and  position 
should  be  of  the  same  size  and  weight  as  nearly  as  pos- 
sible, so  that  the  chuck  will  be  accurately  balanced; 
otherwise,  it  will  be  impossible  to  do  good  work,  and 
besides,  an  extra  strain  will  be  put  on  the  lathe,  which 
may  cause  an  accident.  II,  after  building  a  chuck,  it  is 
found  to  be  out  of  balance,  it  can  be  balanced  by  fasten- 
ing a  block  of  wood  to  the  back  on  the  light  side. 

LUGS   OR   PROJECTIONS   FOR   MACHINISTS'    USE 

Some  castings  must  have  special  parts  cast  on 
them  which  serve  the  purpose  of  holding  them  in  a 


140 


WOOD   PATTERN   MAKING 


machine  while  they  are  being  worked  upon,  but  are 
usually  cut  off  after  the  machine  work  is  completed. 
These  parts  it  is  the  pattern-maker's  business  to  provide 
for  on  the  pattern.  One  form  of  such  a  casting  is  a  piston 
ring  shown  at  Fig.  83.  The  pattern  for  this  should  be 


FIG.  83  FIG.  84 

made  large  enough  so  that  two  to  four  rings  may  be 
made  from  the  same  casting,  leaving  plenty  of  stock  for 
finish.  A  good  allowance  for  this  is  about  one-fourth 
inch  on  each  surface.  The  reason  for  this  extra  allow- 
ance is  that  these  rings  being  comparatively  small  in 
cross  section,  the  metal  must  be  very  clean  and  sound  to 
give  the  required  strength.  As  the  surface  of  castings 
is  usually  more  or  less  porous,  it  is  necessary  to  turn  off 
this  outside  part  in  order  to  get  down  to  the  more  solid 
metal  on  the  inside.  The  pattern  for  a  piston  ring  of 
this  size  should  be  made  as  represented  by  Fig.  84.  The 
projections,  c,  c,  c,  called  lugs,  are  for  the  purpose  of 
bolting  the  casting  to  the  lathe  chuck  while  the  rings  are 
being  turned.  This  is  the  usual  form  in  which  piston 
ring  castings  are  sent  to  the  machine  shop  and  is  the  best 
way  for  this  particular  job.  If  these  lugs  are  not  pro- 
vided, the  machinist  has  to  grip  the  casting  in  a  chuck; 


MISCELLANEOUS   EXAMPLES 


141 


this  is  liable  to  spring  it,  so  that  the  resulting  rings  will 
not  be  true,  as  they  must  be,  to  fit  the  cylinder.  Another 
way  of  providing  for  the  convenience  of  the  machinist  is 
illustrated  by  Fig.  85.  Two  different  methods  are  illus- 


FIG.  85. 

trated  here — one  being  on  the  outside  of  the  casting,  the 
other  on  the  inside.  This  casting  is  the  column  for  a 
small  drill  press.  It  is  finished  the  whole  of  the  distance 
A,  so  it  will  have  to  be  mounted  in  the  lathe  between 
centers.  In  order  that  this  may  be  done,  there  will  have 
to  be  a  boss  cast  on  at  C  and  a  bar  cast  in  across  the  round 
opening  at  B.  This  latter  need  not  be  cut  out, 
as  it  will  be  entirely  hid  and  out  of  the  way  in  the  com- 
pleted machine.  The  boss  at  C  may  be  cut  off  or  allowed 
to  remain  to  suit  the  fancy  of  the  designer.  These  are 
examples  of  simple  contrivances  to  accommodate  the 
machinist. 

FINISHING    PATTERNS 

After  the  woodwork  of  the  pattern  is  completed  it 
must  be  "finished"  by  the  application  of  one  or  more 
coats  of  varnish,  all  small  holes  or  other  defects  in  the 
material  and  workmanship  filled  with  beeswax  and  the 
whole  surface  made  smooth  so  that  it  will  draw  easily. 

This  is  usually  done  in  the  following  manner:   The 


142  WOOD   PATTERN   MAKING 

dust  from  sandpapering  is  all  cleaned  off  with  either 
brush  or  waste  and  then  a  coat  of  moderately  thick 
varnish  is  evenly  applied.  When  this  is  dry  all  nail- 
holes  and  any  defects  in  material  are  filled  with  beeswax ; 
if  any  wax  fillets  are  to  be  put  in  it  should  also  be  done 
at  this  stage.  As  this  first  coat  of  varnish  drys  it  leaves 
the  surface  of  the  wood  slightly  rough ;  this  is  caused  by 
the  wetting  and  drying  of  the  varnish  which  raises  the 
grain  of  the  wood.  This  may  now  be  smoothed  down 
by  sandpapering  it  with  fine  and  partly  worn  sandpaper 
until  it  becomes  smooth  to  the  touch.  This  is  all  that 
needs  to  be  done  if  the  pattern  is  to  be  used  but  once  or 
twice.  If  it  is  to  be  used  frequently  one  or  two  more 
coats  should  be  applied.  For  a  permanent  finish,  several 
thin  coats  will  give  better  results  than  one  or  two  thick 
ones,  and  will  also  make  a  better  appearance.  To  make 
a  very  nice  finish  each  coat  should  be  rubbed  smooth 
with  fine  sandpaper  before  applying  the  next.  When 
patterns  become  rough  from  use  in  the  foundry,  or  from 
any  cause,  they  should  be  cleaned  and  refinished,  for  if  a 
pattern  is  smooth  and  well  finished  it  will  give  the  molder 
little  trouble  and  hence  will  not  receive  such  hard  usage. 
If  a  pattern  is  rough  the  molder  must  rap  and  jar  it  con- 
siderable in  order  to  draw  it,  and  such  treatment  always 
injures  wood  patterns.  In  finishing  patterns  a  varnish 
differing  in  color  from  that  used  for  the  body  of  the  pat- 
tern should  be  put  on  all  core  prints,  so  that  the  molder 
can  tell  at  once  the  general  position  the  cores  will  occupy 
in  the  mold. 

LOOSE   PIECES 

It  is  almost  impossible  to  make  some  patterns  with- 
out loose   pieces,    however   objectionable   they   may   be. 


MITCELLANEOUS   EXAMPLES 


143 


They  are,  however,  in  some  cases  at  least,  preferable  to 
cores.  When  a  choice  must  be  made  between  a  core  and 
a  loose  piece  the  latter  should  generally  be  chosen,  as  it 
will  insure  a  truer  casting.  These  loose  pieces  are  usu- 
ally held  in  place  on  the  pattern  during  the  process  of 
molding  by  skewers  or  draw  pins.  Brads  of  suitable  size 


Fig.  86. 

for  the  job  in  hand  and  bent  to  a  right  angle  near  the 
head  make  good  draw  pins.  In  some  cases  it  is  better 
to  fit  these  loose  pieces  to  the  pattern  with  dovetails, 


144  WOOD   PATTERN   MAKING 

because  when  so  fitted  they  are  less  liable  to  be  pushed 
out  of  place  by  the  molder  in  ramming  the  sand  around 
them.  Another  reason  is  that  the  molder  does  not  have 
to  stop  and  take  out  any  skewers,  but  can  go  right  on 
until  the  mold  is  all  rammed  up.  In  fact  no  notice  need 
be  taken  of  the  loose  pieces  until  after  the  main  part  of 
the  pattern  has  been  pulled.  The  best  way  to  fit  these 
dovetail  pieces  is  to  bevel  them  on  the  edges,  and  also  in 
their  thickness  as  shown  in  Fig.  86.  They  should  be 
fitted  very  accurately  as,  if  they  are  not,  they  are  very 
liable  to  stick  when  drawing  the  pattern.  The  fact  that 
they  are  beveled  in  both  directions  as  suggested  above 
and  shown  in  the  cut  will  almost  always  insure  them 
against  sticking. 

STANDARD    PATTERNS 

Standard  patterns  made  of  wood,  and  often  used, 
should  be  made  as  durable  as  it  is  possible  to  make  them, 
using  hard  wood,  such  as  Mahogany  or  Cherry,  for  all 
the  parts  that  come  in  direct  contact  with  the  sand.  For 
all  parted  patterns  metal  pattern  pins  should  be  used, 
brass  being  the  best.  The  first  cost  is  more,  but  time 
and  labor  required  for  applying  them  is  less,  and  most 
important  of  all,  they  never  stick,  if  properly  fitted  at 
first,  so  that  in  the  "long  run"  they  are  the  cheapest; 
and  standard  patterns  are  usually  made  for  the  "long 
run." 

Rapping  and  draw  plates  should  always  be  fitted  to 
all  standard  patterns,  as  they  will  save  their  cost  in  repair 
work  in  a  very  short  time,  to  say  nothing  about  the  con- 
venience of  the  molder.  There  are  several  kinds  of  these 
plates  on  the  market  at  very  reasonable  prices.  For  any- 
thing except  very  large  patterns,  plates  combining  both 


MISCELLANEOUS   EXAMPLES  145 

rapping  and  drawing  holes  are  the  best.  The  rapping 
holes  in  these  plates  are  simply  drilled,  drawing  or  lifting 
holes  are  taped  to  fit  some  standard  screw  thread. 
Another  method  of  preparing  standard  patterns  for  the 
foundry  is  to  fit  them  to  a  follow  board.  This  is  almost 
always  done  when  a  large  number  of  castings  are  wanted 
off  from  a  pattern  that  requires  an  irregular  parting,  or  if 
the  pattern  is  thin  in  cross  section  and  is  liable  to  be 
injured  by  ramming  the  sand  around  it.  The  cope  side 
of  the  pattern  is  fitted  to  the  top  side  of  the  board  down 
to  where  the  molder  will  make  his  parting,  and  the  board 
cut  to  such  a  shape  as  will  form  the  parting.  This 
follow  board  is  used  the  same  as  a  turn  over  or  mold- 
ing board  in  molding  a  simple  pattern. 

STOVE    PATTERN -MAKING 

The  fundamental  ideas  underlying  the  making  of 
patterns  for  stove  castings  are  practically  the  same  as 
for  machinery  pattern -making;  but  on  account  of  the 
shape  and  generally  delicate  character  of  the  castings 
required,  the  methods  of  their  production  are  in  many 
respects  quite  different.  The  drawings  furnished  the 
stove  pattern-maker  are  also  radically  different  from 
those  sent  to  the  maker  of  machinery  patterns.  Gener- 
ally a  new  design  of  a  stove  is  first  developed  by  making 
a  drawing,  and,  at  the  same  time,  a  model  is  also  worked 
out  in  wax  or  clay,  and  in  some  cases  a  complete  model 
is  made  of  wood. 

This  gives  the  designer  the  opportunity  of  compar- 
ing curves  and  other  ornamental  features  of  the  finished 
stove  which  is  impossible  from  drawings  alone,  and 
enables  him  to  see  how  it  will  be  best  to  have  the  different 
parts  fit  each  other  at  the  many  joints  necessary.  This 


146  WOOD   PATTERN   MAKING 

is  especially  advantageous  in  the  case  of  artistic  heating 
stoves,  on  which  there  is  usually  a  large  amount  of  carv- 
ing. A  model,  however,  is  not  generally  made  in  the 
case  of  plain  work,  such  as  cook  stoves  or  ranges,  these 
being  carried  through  from  drawings  alone.  There  are  also 
several  tools  that  are  used  by  the  stove  pattern-maker 
that  are  not  used  by  others.  These  are  made  necessary 
by  the  requirements  of  the  art ;  one  of  which  is  that  the 
castings,  and  therefore  the  patterns,  must  generally  be  of 
uniform  thickness,  and  comparatively  thin  in  cross  sec- 
tion, usually  not  exceeding  one-tenth  of  an  inch. 

Almost  all  machinery  pattern  drawings  are  made 
and  all  dimensions  given  in  finished  sizes  so  they  may 
be  used  in  the  machine  shop  as  well  as  in  the  pattern 
shop.  Stove  pattern  drawings  seldom  go  farther  than 
the  pattern  shop.  They  are  usually  made  full  size  and 
in  some  cases  at  least,  the  dimensions  are  not  marked  on 
them,  so  that  the  pattern-maker  must  take  the  sizes 
directly  from  the  drawing  by  measuring  it,  and  this  is 
usually  done  with  trams  and  applied  to  the  shrink  rule 
to  be  used.  The  plan  is  first  drawn  and  then  the  eleva- 
tions or  side  views  are  drawn  in,  usually  on  the  same 
paper  so  that  the  lines  of  each  view  are  all  mixed  up, 
which  makes  the  reading  of  them  very  difficult  for  those 
unfamiliar  with  this  kind  of  work.  Sometimes  the  lines 
of  these  different  views  are  made  with  different  colors, 
so  as  to  be  the  more  easily  read.  The  same  shrink  rule 
to  be  used  in  making  the  original  patterns  is  used  by  the 
draftsman  in  making  these  drawings. 

The  stove  wood  pattern-maker  is  provided  with 
from  five  to  seven  different  shrink  rules ;  the  one  to  be 
used  for  any  given  pattern  is  determined  by  the  kind  of 
metal  of  which  the  master  pattern  is  to  be  made  and  also 


MISCELLANEOUS    EXAMPLES  147 

the  method  of  producing  it.  These  rules  are  spoken  of 
as  one  shrink,  two  shrink,  or  one  and  a  half  shrink 
according  to  the  ratio  of  the  rule  to  the  standard  rule. 
The  word  "shrink"  in  this  instance  meaning  the  general 
amount  allowed  in  making  machinery  patterns,  viz:  one- 
eighth  inch.  Which  one  of  these  is  to  be  used  is  de- 
termined by  the  material  to  be  used  in  the  production  of 
the  master  pattern. 

Because  of  the  necessity  of  beveling  the  edges  of  all 
stove  plates  where  they  come  together,  and  to  have 
these  bevels  uniform  throughout  the  stove,  it  has  been 
found  advantageous  by  stove  pattern-makers  to  have  a 
set  of  "bevel  gauges"  for  measuring  and  laying  out  these 
bevels.  Such  a  set  of  bevel  gauges  was  originated  by 
Mr.  N.  Vedder,  formerly  a  stove  designer  of  Troy,  N.Y., 
and  which  have  come  into  extensive  use  among  stove 
manufacturers  during  the  last  few  years.  In  order  that 
these  gauges  may  be  convenient  for  use,  they  are  made 
of  thin  wood  or  metal  similar  to  the  triangles  used  in 
making  mechanical  drawings.  There  are  eight  of  these 
bevels  in  use  ranging  from  one  of  about  2°  to  that  of  30°, 
which  is  the  largest  angle  used.  These  are  numbered  as 
follows :  From  two  degrees  to  eight  degrees  are  four 
bevels  numbered  by  ciphers,  two  degrees  being  desig- 
nated by  0000,  the  next  by  000,  the  next  by  00,  and  the 
next  by  0,  which  is  eight  degrees.  The  other  four  bevels 
are  designated  by  the  numerals  1,  2,  3,  4,  number  one 
being  an  angle  of  10°,  number  two,  16/^°,  number  three, 
23//i°,  and  number  four,  30°.  As  in  a  large  part  of  stove 
patterns  it  is  necessary  to  make  them  of  curved  outline, 
and  as  these  curves  cannot  very  well  be  marked  out 
with  trams,  a  set  of  standard  curves  have  been  adopted. 
These  are  used  by  having  them  made  up  of  thin  wood  or 


148  WOOD    PATTERN   MAKING 

metal  (metal  being  best)  so  they  may  be  used  in  the  same 
way  as  the  bevel  gauges.  These  are  likewise  used  by 
both  draftsman  and  pattern-maker. 

It  sometimes  becomes  necessary  to  make  a  center 
line  across  a  carved  or  other  uneven  surface.  For  this 
purpose  a  simple  contrivance  known  as  a  "vertical 
plumb"  has  been  devised.  It  consists  of  two  boards 
fastened  together  lengthwise  'at  their  edges  and  at  right 
angles  to  each  other.  This  must  be  set  up  on  two  par- 
allel blocks  of  such  a  height  as  will  raise  it  above  a  pat- 
tern or  other  object  on  which  it  is  required  to  make  a 
straight  line  across  the  uneven  surface.  A  scriber  with 
which  to  make  the  mark  is  also  needed.  This  consists 
of  a  thin  flat  piece  of  wood  on  which  is  fastened  a  thin 
plate  of  steel  sharpened  to  a  keen  cutting  edge. 

Stove  patterns  must  be  carved  very  thin  and  made 
of  uniform  thickness  throughout.  If  they  are  not  the 
castings  will  not  be  of  even  thickness,  so  that  one  part 
will  cool  more  rapidly  than  others,  thereby  causing  them 
to  warp  and  sometimes  to  crack  from  the  shrinkage 
strains.  To  insure  that  the  patterns  are  of  unifoim 
thickness,  a  special  form  of  calipers  are  used  for  meas- 
uring their  thickness.  These  calipers  are  made  with  a 
loose  joint  something  like  a  pair  of  shears.  Just  at  the 
back  of  these  shear-like  handles  are  short  projections, 
through  one  of  which  a  screw  is  put,  the  end  of  the  screw 
abutting  against  the  other.  The  points  of  the  caliper 
may  be  set  to  a  definite  distance  apart,  the  above  screw 
turned  in  until  its  end  comes  in  contact  with  the  other 
projection  mentioned.  The  calipers  may  now  be 
opened  and  passed  over  any  intervening  thick  part  of  a 
pattern  and  the  points  closed  again  to  the  same  distance 
as  before.  Now  if  the  screw  does  not  touch,  or  come  to 


MISCELLANEOUS    EXAMPLES  149 

a  bearing,  the  pattern  is  too  thick  at  that  point  and  must 
be  pared  down.  Most  stove  plate  work  is  very  uneven 
on  the  surface  on  account  of  the  carving  and  other  orna- 
mental work.  In  order  that  the  pattern  may  be  of  equal 
thickness  it  has  to  be  "backed  out,"  as  it  is  called,  that 
is,  it  has  to  be  carved  out  on  the  back  to  conform  to  the 
shape  of  the  carving  on  the  front.  This  makes  it  neces- 
sary that  the  outlines  of  the  carving  be  transferred  to  the 
back.  This  is  most  easily  and  accurately  done  by  the  use 
of  what  are  known  as  "marking  calipers."  These  are 
usually  made  of  hard  wood  and  similar  in  shape  to  the 
ordinary  wing  caliper  that  is  hinged  together  at  the  end 
of  what  may  be  called,  the  handle.  One  leg  is  provided 
with  a  steel  point,  the  other  with  a  pencil  point.  A 
spring  is  set  in  between  the  two  parts  of  the  handle  that 
tends  to  open  the  points,  so  that  in  order  to  bring  the 
points  together  this  spring  must  be  compressed.  By  fol- 
lowing the  outline  of  the  carving  with  the  steel  point, 
and  at  the  same  time  compressing  the  spring  and  keeping 
the  pencil  point  in  contact  with  the  back  of  the  pattern,  the 
outline  may  be  accurately  and  rapidly  transferred  to  that 
side.  Many  parts  of  stove  patterns  have  to  be  joined  on 
an  angle,  and  as  the  stock  is  generally  very  thin,  it  is 
quite  difficult  to  joint  the  edges  to  the  correct  angles, 
therefore  it  is  necessary  that  some  device  be  provided 
for  holding  the  stock  in  fixed  position  with  regard  to  the 
plane.  For  this  purpose  some  form  of  shoot  board  is 
found  useful.  One  form  of  shoot  board  is  represented 
by  Fig.  54  on  page  96.  For  stove  pattern  work,  how- 
ever, it  must  be  more  complicated  than  is  this,  as  it  is 
necessary  that  it  be  adjustable  to  several  different  angles, 
and  be  set  accurately  to  any  given  angle  within  its  lim- 
its. As  a  large  amount  of  carving  is  necessary  in  stove- 


150  WOOD   PATTERN   MAKING 

pattern -making  which  cannot  be  done  with  the  chisels 
and  gouges  of  the  ordinary  pattern-maker's  outfit,  the 
stove  pattern-maker  is  provided  with  a  series  of  carving 
tools,  usually  about  twenty  in  number.  In  large  estab- 
lishments making  stove -patterns,  the  carving  is  usually 
done  by  men  especially  skilled  in  that  work,  and  in  some 
cases  stove -patterns  pass  through  the  hands  of  several 
men,  each  doing  his  own  special  kind  of  work.  A  large 
quantity  of  very  thin  stock,  some  of  which  is  less  than 
one -twelfth  inch  in  thickness  is  required  for  this 
class  of  patterns.  As  this  cannot  very  well  be 
made  on  the  ordinary  planer  without  some  special 
attachment  a  suitable  one  is  provided  for  the  planer  in 
stove  pattern  shops  with  which  thin  boards  may  be 
planed  smoothly  and  to  a  uniform  thickness. 

Almost  all  machinery  patterns  are  fairly  thick  and 
stiff  enough  of  themselves  for  the  purpose  of  molding; 
moreover,  in  the  production  of  this  class  of  patterns,  the 
application  of  the  principles  of  joinery  is  an  important 
part.  Stove  patterns  are  usually  very  thin,  and  practi- 
cally of  uniform  thickness  throughout  and  therefore 
require  special  treatment.  Stove  patterns  are  rarely  stiff 
enough  of  themselves  for  the  purposes  of  molding  and 
must  be  supported  by  what  is  called  a  "match"  during 
the  process  of  molding  to  produce  the  metal  patterns. 
The  match  is  very  frequently  made  first  and  the  pattern 
made  or  built  on  it.  In  many  cases  these  patterns  are 
very  intricate  having  quite  a  large  amount  of  carving  on 
them. 

Because  of  these  many  facts,  stove  pattern -making 
differs  considerably  from  ordinary  pattern -making  and 
is  a  distinct  branch  of  the  art.  The  original  pattern  for 
stove  work  is  usually  made  of  wood;  in  some  shops, 


MISCELLANEOUS   EXAMPLES  151 

however,  original  patterns  are  sometimes  modeled  in 
clay  or  plaster -of -Paris.  From  this  original  pattern  a 
master  pattern  is  made  of  iron.  For  this  purpose,  how- 
ever, some  foundries  use  a  white  metal  alloy  consisting 
of  nine  parts  lead  and  one  part  antimony,  which  has  a 
shrinkage  of  one -sixteenth  inch  per  foot.  This  is  pre- 
served and  from  this  the  pattern  to  be  used  in  the  pro- 
duction of  the  castings  for  the  stoves  is  made.  The 
original  wood  patterns  are  rarely  kept  as  they  are  sure  to 
change  their  form.  There  are  several  distinct  processes 
used  in  making  stove -patterns,  but  on  account  of  space 
they  cannot  be  described  and  will  for  that  reason  be  just 
barely  mentioned.  One  of  these  is  what  is  known  as  the 
"carving  and  backing  out  wooden  patterns."  This  is 
the  simplest,  and  means  that  the  pattern  is  carved  out  of 
wood  to  the  exact  shape  and  thickness.  For  a  small 
pattern,  like  a  stove  leg  for  instance,  this  would  be  all 
that  is  necessary  from  which  to  make  the  mold  for  the 
master  pattern.  For  large  patterns  in  this  process,  how- 
ever, a  match  or  follow  board  must  be  made  to  support 
the  pattern  while  ramming  up  the  nowel.  Another  dis- 
tinct process  is  the  "wax  process."  This  is  used  to 
avoid  backing  out  the  wooden  pattern.  Considerable 
practice  or  experience  is  necessary  to  work  this  method 
successfully.  Then  there  is  the  "carving  and  blocking" 
process,  in  which  the  molder  surrounds  the  pattern  with 
a  thin  layer  of  blocking  just  the  thickness  of  the  required 
casting,  when  ramming  up  the  drag.  In  all  these  pro- 
cesses the  block  of  wood  used  for  the  pattern  is  "built 
up"  of  thin  pieces  of  wood,  so  as  to  reduce  the  effects  of 
shrinking  and  swelling  to  the  minimum.  In  many  stove 
patterns  allowance  has  to  be  made  for  the  warping  of  the 
casting.  This  is  usually  done  by  preparing  a  special 


152  WOOD   PATTERN    MAKING 

form  of  mold  board  which  is  curved  so  as  to  give  the 
required  curve  to  the  pattern,  as  it  is  built  on  to  and  over 
the  mold  board.  This  is  necessary  because  a  casting 
made  from  a  straight  pattern  often  comes  out  warped  or 
bent  so  that  it  is  necessary  to  bend  the  pattern  in  the 
opposite  direction,  so  that  the  casting  will  come  out 
straight. 


Appendix 


READING  MECHANICAL  ( WORKING)  DRAWINGS 

Mechanical  drawing  has  been  defined  as  the  univer- 
sal "language  of  the  engineer."  A  drawing  made  in 
one  country  can  be  read  and  worked  to  in  another,  that 
is,  the  drawing  proper.  Notes  on  the  drawing  in  the 
language  of  a  country  could  not  be  read  except  by  one 
acquainted  with  its  language;  and,  the  unit  of  measure- 
ment also  might  be  different,  but  the  main  idea  repre- 
sented by  the  drawing  would  be  readily  apprehended. 

One  who  desires  to  read  working  drawings  and  get 
from  them  the  information  they  are  intended  to  convey, 
must  know  something  of  the  principles  underlying  their 
construction,  and  the  conventionalities  used.  All  work- 
ing drawings  are  made  on  the  principle  of  orthographic 
projection,  usually  spoken  of  simply  as  projection  draw- 
ings. That  is,  all  the  imaginary  lines  of  sight,  (projec- 
tors) ,  are  parallel,  and  perpendicular  to  the  picture  plane. 
There  are  three  principal  VJCWS,  or  elevations,  as  they  are 
called,  used  in  the  representation  of  objects  by  drawings, 
viz. :  the  plan,  or  top  view,  and  end  or  side  View,  called  in 
descriptive  geometry  the  three  planes  of  projection.  It 
is  sometimes  necessary  to  introduce  a  fourth  VJCW,  which 

becomes  a  second  end  or  side  view.    Each  of  these  views  is 

drawn  so  as  to  represent  the  different  sides  of  the  object 
at  right  angles  to  each  other.  When  some  parts  of  an 
object  extend  at  an  angle  other  than  a  right  angle, 


APPENDIX  155 

auxiliary  views  are  projected  on  the  center  lines  of  these 
angular  parts,  in  order  to  show  their  true  shape.  In  the 
representation  of  simple  or  symmetrical  objects,  one  view 
is  omitted,  usually  the  plan,  as  it  is  not  necessary. 
Many  objects  or  parts  of  machinery,  (with  which  the 
pattern-maker  has  most  to  do),  can  be  represented  with 
sufficient  clearness  by  two  views.  When  these  do  not 
clearly  delineate  the  object,  the  third,  and  if  neces- 
sary a  fourth  is  used. 

The  obscured  parts  of  a  simple  object,  that  is,  parts 
that  do  not  appear  on  the  surface  represented,  are  shown 
by  broken  lines.  In  complicated  objects  this  is  not 
practicable  because  of  the  many  lines  that  become  neces- 
sary, which  would  be  confusing  and  lead  to  mistakes. 
When  for  this  reason  this  method  of  broken  lines  is  not 
feasible,  it  is  customary  to  imagine  the  object  cut,  or 
that  an  assumed  plane  has  been  passed  through  it,  and  the 
surface  thus  produced  exposed.  'A  drawing  of  such  a 
surface  is  called  a  section,  and  indicates  the  shape  of  a 
piece  at  the  place  cut  by  an  imaginary  plane.  A  piece  of 
varying  section  may  be  cut  by  planes  at  as  many  places 
as  is  desired,  and  the  section  shown  at  each.  Complete 
sectional  views  show  not  only  the  parts  cut  by  this 
assumed  plane,  but  also  any  other  parts  of  the  object 
which  may  be  seen  beyond.  Such  sectional  views  are 
usually  made  by  passing  a  plane  through  the  line  of 
centers,  or  other  line  of  symmetry.  To  indicate  the  cut 
surface  of  a  section  it  is  rilled  with  uniformly  spaced 
diagonal  lines.  This  is  called  cross-hatching.  Different 
pieces  of  material  appearing  in  the  same  section  are  indi- 
cated by  the  lines  running  in  different  directions.  Dif- 
ferent materials  are  indicated  by  using  different  kinds  or 
grouping  of  lines.  An  incomplete  section  shows  the 


156  WOOD   PATTERN   MAKING 

objects  partly  in  full  elevation,  and  partly  in  sectional 
elevation.  Such  drawings  are  also  called  broken  draw- 
ings. Long,  symmetrical  parts,  as  a  piece  of  shafting, 
may  be  shown  by  making  drawings  of  the  ends  close 
together  with  the  middle  portion  broken  out.  These 
are  also  called  broken  drawings,  and  are  used  to  save 
space  or  to  get  a  long  piece  on  a  small  sheet. 

Various  arrangements  of  views  on  a  drawing  are 
possible,  each  of  which  will  be  equally  effective  in 
conveying  the  necessary  information.  Attempts  have 
been  made  to  establish  uniformity  of  practice  in  this 
respect,  withoat  effect,  for  the  reason  that  such  a  vast 
variety  of  forms  are  encountered,  and  difficulties  of 
execution  are  met  in  practical  work,  that  in  general  it  is 
not  possible  to  follow  any  cut  and  dried  rules.  When 
making  drawings  for  use  in  engineering  construction, 
especially  for  workshop  use,  that  draftsman  is  the  best 
one  who  can  convey  the  necessary  information  with  the 
least  expenditure  of  time  and  labor  spent  in  making  the 
drawing,  consistent  with  neatness  of  execution  and 
accuracy  of  dimensions.  About  three  things  must  be 
kept  in  mind  in  making  or  interpreting  a  drawing. 

First — Each  view  of  the  part  of  machine  or  structure 
represented  must  be  a  projection  of  the  adjacent  view  of 
the  same  object. 

Second — It  must  be  clear  which  end  or  side  view  is 
shown  in  the  adjacent  view,  whether  it  is  the  end  or  side 
nearest  the  adjacent  view,  or  the  one  farthest  from  it. 

Third — In  the  case  of  unsymmetrical  parts  it  is  neces- 
sary to  be  sure  whether  the  piece  to  be  made  is  "Right 
hand"  or  "Left  hand." 

These  last  are  shop  terms  that  have  originated  in 
practice,  and  may  be  illustrated  by  considering  a  photo- 


APPENDIX 


157 


graph  and  its  negative.  An  object  appearing  on  the  right 
side  of  the  photograph  will  appear  on  the  left  side  of  the 
negative,  and  the  whole  picture  is  reversed.  Suppose 
the  pattern  being  made  is  curved  on  one  side  and  straight 
on  the  other,  we  must  be  sure  which  side  is  straight  and 
which  curved. 

A  good  general  method  of  procedure  in  reading  a 
working  drawing  is  as  follows :  First,  ignore  for  the  time 
being  the  dimensions  and  dimension  lines  entirely  until 
an  idea  is  obtained  and  fixed  in  the  mind  of  the  general 
shape  of  the  object.  Second,  refering  to  the  several 


2t 


FIG.  1  (d) 

views,  notice  if  its  outline  is  to  be  a  cylinder,  a  cube,  a 
cone,  etc.,  or  a  combination  of  several  of  these  element- 
ary forms.  This  being  clearly  impressed  on  the  mind, 


158  WOOD   PATTERN   MAKING 

observe  how  it  is  modified  by  details,  and,  always  refer  - 
ing  to  the  several  views,  determine  whether  they  project 
from  the  main  body,  or  are  recesses  or  holes.  Finally 
form  an  idea  of  the  relative  sizes  of  the  component  parts 
by  refering  to  the  dimensions.  Pay  strict  regard  to  all 
conventional  representations  that  have  been  used. 

At  Fig.  1  (d)  is  shown  how  the  views  are  usually 
arranged  when  three  views  of  an  object  are  given.  This 
arrangement  may  be  modified  when  some  other  will  bet- 
ter convey  the  meaning.  If  still  another  view  was 
thought  necessary  to  represent  the  object  as  it  would 
appear  when  looking  at  its  left  side  it  would  be  located 
at  the  left  of 'the  front  view;  this  would  be  called  the  left 
side  view.  In  the  drawing,  "A"  is  the  plan  or  top  view, 
"B"  is  the  front  view,  and  "C"  is  the  right  side  view. 
These  names  are  purely  arbitrary-  and  are  used  only  as 
conventionalities,  as  any  side  of  the  object  may  be 
assumed  as  the  front  view  except  when  the  object  has  a 
natural  base,  as  a  table,  or  a  machine,  etc.  Then  the 
top  view  would  be  a  drawing  of  the  top  side  of  the 
machine  as  it  stood  in  its  normal  position,  that  is,  on  its 
natural  base. 

One  good  way  of  determining  the  shape  of  an  object 
from  a  drawing  is  to  imagine  the  paper  on  which  the 
drawing  is  made  to  be  bent  on  a  line  somewhere  between 
two  of  the  views  until  the  surfaces  are  perpendicular  to 
each  other,  or  actually  bending  the  paper  with  the  draw- 
ing on  it  in  this  manner,  then  imagine  some  object  that 
if  projected  on  the  two  planes  would  give  outlines  like 
the  ones  shown  on  the  drawing,  treating  sectional  views 
in  the  same  manner  as  full  views. 

On  page  159  is  introduced  a  working  drawing  of  the 
headstock  of  a  lathe.  It  illustrates  several  of  the  pre- 


APPENDIX 


159 


160 


WOOD   PATTERN   MAKING 


viously  mentioned  conventions.  One  of  these  is  the 
arrangement  of  the  views,  which  is  different  from  that  of 
Fig.  1  (d).  In  Fig.  2  (d),  the  plan,  (A)  is  below  the 
front  view  (B),  therefore  the  front  view  shows  the  side 
of  the  plan  that  is  the  farthest  from  it.  In  Fig.  1  this  is 
reversed;  but  this  does  not  interfere  with  the  interpreta- 
tion of  either,  as  when  any  one  of  the  views  is  studied 
with  relation  to  the  others  the  form  of  the  object  can  be 
readily  imagined. 

What  is  known  as  a  "broken  drawing"  is  also  illus- 
trated in  this  figure  at  D  and  D.     In  this  case  one -half 


FIG.  3  (d) 

of  the  object  is  supposed  to  be  broken  away,  and  a  view 
given  as  the  object  appears  at  that  point  after  its  removal ; 
this  makes  it  easily  understood  as  to  the  desired  shape. 
Another  convention  illustrated  is  the  method  of  indicat- 
ing which  surfaces  are  to  be  machined.  It  is  by  the  use 
of  the  letter  F,  placed  on  or  near  the  surface  to  be 
machined  or  finished.  One  method,  (broken  lines)  of 
indicating  the  location  and  size  of  tapped  holes  for  the 


APPENDIX  161 

reception  of  bolts  is  also  shown  in  the  center  of  each 
bearing.  Fig.  3  (d)  shows  one  way  of  representing 
simple  circular  objects  that  is  used  quite  frequently  in 
machine  drawings.  The  sectional  view  is  a  complete 
section. 

LUMBER 

Lumber  is  produced  by  sawing  trunks  of  trees 
lengthwise  into  planks  or  boards  of  commercial  sizes.  In 
order  to  produce  special  sizes  and  shapes,  the  sawing  is 
done  in  several  different  directions  without  regard  to  the 
grain  of  the  wood.  There  are,  however,  two  general 
directions  or  methods  used,  by  one  or  the  other  of  which 
the  larger  part  of  all  lumber  is  produced.  One  of  these 
is  called  Straight  or  bastard  sawing;  the  other  quarter  saw- 
ing. Straight  sawn  lumber,  sometimes  called  "rift 
sawn,"  is  produced  by  passing  the  saw  through  and 
through  the  log,  without  any  regard  to  the  grain.  Quarter- 
sawn  lumber  is  made  by  passing  the  saw  through  the 
log  approximately  parallel  with  the  medullary  rays,  or 
radially  with  the  log.  There  are  several  ways  of  doing 
this,  one  of  which  is  as  follows:  The  log  is  first  squared 
and  then  sawn  into  four  quarters.  Each  one  of  these  is 
set  on  the  carriage  of  the  sawing  machine  so  that  the  saw 
will  pass  through  it  diagonally.  The  sides  of  the  center 
board  will  then  be  parallel  with  the  medullary  ray. 
This  method  gave  rise  to  the  term  "quarter  sawn." 
The  larger  part  of  the  lumber  produced  is  made  by 
the  first  method.  The  last  is  very  wasteful  of  timber, 
and  the  product  is  therefore  much  more  expensive. 

If  the  trunk  of  a  tree  is  cut  transversely,  it  is  found 
to  be  composed  of  a  series  of  concentric  cylindrical  lay- 
ers, the  cross  sections  of  which  form  rings  that  are  quite 


162  WOOD   PATTERN    MAKING 

distinct  from  each  other.  These  layers  are  formed,  one 
each  year  during  the  period  of  the  tree's  growth.  They 
vary  in  thickness  in  different  kinds  of  wood,  and  in  dif- 
ferent specimens  of  the  same  kind.  They  also  vary  in 
density  and  color;  the  more  dense  or  hard  are  always 
found  near  the  heart.  These  variations  are  due  to  the 
difference  in  rapidity  of  growth,  length  of  season,  and 
other  circumstances  that  may  change  from  year  to  year. 
The  location  and  soil  in  which  the  tree  grew  also  modifies 
to  a  degree  the  above  characteristics  of  these  layers.  It 
is  these  layers  of  woody  fiber  that  give  to  boards  the 
appearance  called  "the  grain."  This  appearance  varies 
according  to  the  position  the  board  occupied  in  the  log. 
The  part  of  the  wood  next  to  the  bark  is  called  "sap 
wood" ;  all  on  the  inside  of  this  is  called  "heart  wood." 
Heart  wood  is  generally  more  dense,  of  a  darker  color, 
and  is  much  more  durable  than  sap  wood.  During  favor- 
able weather  the  sap  of  the  tree  circulates  through  the 
sap  wood,  but  during  the  winter  it  is  supposed  to  cease; 
it  is  this  period  of  non- circulation  of  sap  that  causes  the 
distinct  lines  that  appear  between  successive  annual  rings. 
The  darker  color  and  greater  density  of  heart  wood  is 
caused  by  the  closing  up  of  its  cells  by  the  gums  of  the 
wood  that  were  previously  held  in  solution;  for  this 
reason  it  is  nearly  or  quite  impervious  to  sap.  There  is 
a  difference  in  the  proportion  of  sap  wood  in  different 
kinds  of  trees,  and  in  different  individuals  of  the  same 
species.  The  slower  growing  trees  usually  have  the 
least. 

For  a  tree  to  afford  the  best  quality  of  lumber  it 
should  not  be  cut  until  it  has  arrived  at  maturity.  The 
oak  is  said  to  reach  this  period  in  about  100  years,  the 
pine  in  70  to  100  years,  and  ash  and  elm  at  from  50  to 


APPENDIX  163 

100  years.  Midwinter  or  midsummer  are  the  seasons  of 
the  year  best  adapted  for  the  felling  of  timber  to"  secure 
the  best  quality  of  lumber.  The  principal  reason  for  this 
is  the  fact  that  at  these  seasons  the  trunk  of  the  tree  con- 
tains less  sap  than  at  others. 

Seasoning  lumber  is  driving  Ollt  the  Waterfrom  its  pores. 
This  may  be  done  by  natural  or  artificial  means.  However 
it  is  done  it  should  be  a  slow  process,  especially  in  its  first 
stages,  therefore,  natural,  or  air  seasoning,  gives  the  best 
results.  Koran}'  purpose  where  strength  or  permanence 
of  form  is  very  desirable,  it  is  best  to  properly  "stick 
up"  the  lumber  in  a  seasoning  shed  that  will  protect  it 
from  the  sun,  rain,  and  snow,  for  at  least  one  year,  and 
then  put  it  in  a  drying  kiln  to  complete  the  process.  If 
lumber  is  put  into  the  kiln  when  green,  the  water  is 
driven  out  so  rapidly  by  the  high  temperature  that  it  car- 
ries with  it  more  or  less  of  the  gums  of  the  wood.  This 
is  prevented  by  "sticking  up"  in  the  shed,  as  during  the 
time  it  is  under  these  natural  conditions  the  process  is 
comparatively  very  slow .  All  these  gums  should  be  retain  - 
ed ,  if  possible ,  as  they  add  strength  and  density  to  the  lum  - 
ber,  and  the  more  dense  wood  is,  other  things  being  equal, 
the  more  permanent  will  be  its  form  under  varying  con- 
ditions of  the  humidity  and  the  temperature  of  the  sur- 
rounding atmosphere.  Conversly,  then,  if  these  gums 
are  driven  out  during  the  process  of  seasoning,  the  wood 
is  not  as  strong,  and  is  more  porous,  also,  and  will 
therefore  absorb  and  give  off  moisture  more  readily, 
which  will  interfere  with  its  permanence  of  form.  Lum- 
ber cannot  be  so  well  seasoned  as  not  to  shrink  when 
placed  in  a  dryer  atmosphere. 

If  wood  is  placed  in  air  that  is  quite  dried  of  its 
moisture,  it  will  continue  to  retain  a  portion  of  its 


164  WOOD   PATTERN   MAKING 

original  moisture.  A  log  taken  from  a  freshly  cut  tree 
(green)  contains  about  50  percent,  by  weight,  of  water. 
(The  sap  wood  contains  more  than  this  percentage,  the 
heart  wood  less).  When  the  log  (stripped  of  its  bark), 
is  allowed  to  remain  in  the  open  air,  more  than  half  of 
this  water  will  evaporate  in  a  few  months.  If  it  is  sawn 
into  lumber  and  "stuck  up"  in  a  seasoning  shed,  the 
water  will  be  further  reduced  to  from  12  to  15  per  cent, 
of  the  total  weight;  if  it  is  put  into  an  ordinary  living 
room  it  will  be  reduced  to  from  8  to  10  per  cent. ;  if  it  is 
put  into  a  drying  kiln  operating  at  a  temperature  of  from 
160°  to  180°  F.,  only  from  2  to  4  per  cent,  of  water  will 
be  left ;  but  though  the  temperature  be  raised  to  300° 
F.  (when  chemical  destruction  begins),  water  will  still 
be  given  off.  Immediately  after  wood  is  taken  out  of  a 
kiln  it  begins  to  absorb  moisture.  In  a  week  it  will 
have  regained  from  5  to  6  per  cent,  of  moisture;  in  a 
month  or  so,  its  condition,  if  kept  in  the  open  air,  will 
be  normal — that  is,  12  per  cent,  of  its  weight  will  be  due 
to  the  water  it  contains.  Whenever  wood  gives  off 
moisture  it  shrinks.  Green  wood  will  by  seasoning 
shrink  about  8  per  cent,  of  its  width  across  the  grain. 
One  of  the  objects  of  seasoning  is  to  reduce  the  moisture 
to  the  proportional  limit  that  will  obtain  between  the 
wood  and  the  air  with  which  it  will  be  surrounded  after 
it  is  manufactured  into  some  article  of  use  or  ornament. 
Neither  air  seasoning  nor  kiln  drying  at  a  temperature 
below  200°  F.,  will  affect  the  capacity  of  wood  for  taking 
up  moisture  when  there  is  an  excess  of  humidity  in  the 
air,  and  whenever  wood  takes  up  moisture  it  increases 
in  size  (swells). 

This  faculty  in  wood  of  resuming  original  size,  of 
being  larger  or  smaller,  according  to  atmospheric  con- 


APPENDIX  165 

ditions,  is  one  of  the  most  difficult  problems  with  which 
wood -workers  have  to  deal.  To  paint  wood -work,  or  to 
varnish  it  makes  little  difference  to  these  qualities ;  these 
coatings  simply  retard  these  changes,  they  do  not  over- 
come them.  For  these  reasons,  whenever  it  is  required 
to  cover  large  areas  with  wood -work,  some  method  must 
be  adopted  to  nullify  the  effect  of,  or  of  concealing 
altogether,  the  "working"  of  the  various  pieces  of  wood 
after  they  are  placed  in  position.  The  combined  precau- 
tions of  intelligent  framing,  and  the  application  of  pro- 
tective coatings  fail  to  secure  immunity  from  these 
hygroscopic  effects.  Wood  is  doubly  affected  by  the 
cold,  damp  air  of  the  winter  months.  By  the  natural  or 
air  seasoning  process,  two  years  for  small  or  thin,  and 
four  years  for  large  or  thick  lumber  is  necessary  to 
secure  good  results;  lumber  is,  however,  rarely  over- 
seasoned.  It  may  be  much  more  rapidly  seasoned  by 
high  temperatures  in  drying  kilns.  It  is  not  impossible 
to  season  one -inch  thick  boards  by  this  means  in  two 
days,  but  it  "kills  the  life"  of  the  timber.  As  a  rule, 
the  softer  a  wood  is,  the  more  readily  it  will  shrink  or 
swell.  Great  care  should  be  taken  in  preparing  the 
foundation  on  which  to  pile  lumber  for  the  purpose  of 
seasoning  it.  The  edges  of  the  timbers  on  which  the 
boards  are  laid  should  all  be  in  the  same  plane,  so  that 
the  boards  (which  will  retain  the  shape  given  to  them 
by  the  pile),  may  be  true  planes  when  taken  out  of  the 
pile  after  seasoning. 

Warping  in  wood  is  a  change  Of  form  result- 
ing from  unequal  shrinking  or  swelling.  It  is 
sometimes  caused  by  unequal  exposure;  in  fact  this  is 
its  most  fruitful  cause.  When  a  board  is  so  placed  as 
that  one  side  is  exposed  to  the  direct  rays  of  the  sun  or 


166  WOOD   PATTERN    MAKING 

other  heat,  and  the  other  to  a  damp  atmosphere,  the 
first  side  will  become  concave.  A  board,  especially  a 
green  one,  will  also  warp  when  it  is  equally  exposed, 
that  is,  when  it  is  surrounded  by  equally  dry  air.  The 
cause  of  this  is,  that  the  board,  because  of  the  arrange- 
ment of  its  cells,  gives  off  the  moisture  it  contains  more 
rapidly  from  one  side  than  the  other.  The  side  that  dries 
first  will  become  concave.  Now  if  a  board  is  cut  from  a 
log  midway  between  the  heart  and  sap,  there  will  be  a 
larger  number  of  the  cells,  (which  lie  parallel  to  the 
sides  of  the  annual  layers),  opened  on  the  sap  side; 
therefore,  moisture  will  be  given  off  more  rapidly  from 
that  side,  and,  as  wood  always  shrinks  when  it  gives  off 
moisture,  that  side  will  shrink  first  and  become  concave 
and  the  heart  side  convex.  The  medullary  rays,  as  they 
shrink,  also  conduce  to  this  form  in  a  slight  degree. 

If  these  facts  are  kept  in  mind,  and  the  end  of  a 
board  is  examined  it  may  be  known  in  what  direction 
the  board  will  warp,  when  any  of  the  above  conditions 
obtain  as  to  its  surroundings.  Quarter-sawn  lumber  is 
cut  radially  to  the  log,  and  so  does  not  contain  these 
characteristics,  therefore  will  not  warp  much. 

From  these  facts,  then,  the  following  principle  may 
be  deduced :  In  all  wood  work,  the  heart  side  of  the 
board  should  always  be  placed  on  the  side  of  the  work 
that  will  be  the  most  exposed  to  any  change  that  is  likely 
to  take  place  in  the  surrounding  atmospheric  conditions, 
for  the  reason  that  it  is  the  least  susceptible  to  change 
of  the  two  sides. 

Because  of  the  above  noted  characteristics  of  wood, 
it  is  best  to  cut  the  pieces  to  be  used  in  any  construction 
roughly  to  size,  and  allow  them  to  stand  for  some  time 
before  they  are  cut  to  the  finished  size.  If  this  is  done, 


APPENDIX  167 

they  may  warp  into  a  more  permanent  form,  and  so  will 
be  less  likely  to  change  the  form  of  the  final  construc- 
tion. A  board  that  has  recently  been  planed  to  a  true 
surface  should  not  be  left  lying  flat  on  the  bench,  as  it 
will  warp  and  become  concave  on  the  upper  side.  This 
is  due  to  the  greater  exposure  of  the  upper  surface  com- 
pared with  the  under,  which  remained  in  contact  with 
the  bench.  A  board  having  reasonably  straight  grain, 
and  which  has  been  planed  to  a  true  surface  all  over, 
should  be  left  on  its  edge  or  end. 

TOOLS   FOR    BENCH   WOODWORK 

For   all   hand  wood   work  the    bench   is  the    first 
requisite.     The  best  form  of  bench  for  pattern -making 


FIG.  1. 


is  that  illustrated  by  Fig.  1.     If  this  is  fitted  with  a  No. 
1  "Emmert"  Pattern -Maker's  Universal  Vise,  shown  by 


168  WOOD   PATTERN   MAKING 

Fig.  1  (a),  instead  of  the  one  shown  at  the  head  of  the 
bench ,  it  will  be  the  best  that  can  be  obtained  for  this  part  of 


FIG.  1 


shop  equipment.  The  bench  hook  is  a  very  useful  part  of 
bench  equipment,  one  form  of  which  is  shown  at  Fig. 
2 ;  it  should  be  twelve  to  fourteen  inches  long.  Some 
form  of  saw -horse  is  also  a  necessary  part  of  pattern  shop 


FIG.  2. 


equipment;  a  handy  and  easily  built  form  is  shown  at 
Fig.  3.  Another  almost  indispensable  article,  something 
like  a  bench  in  its  nature,  is  what  is  known  as  a  laying 
OUt  table,  or  large  drawing  board,  on  which  work  can  be 
laid  out  at  full  size  when  necessary.  It  should  be  built 


APPENDIX  169 

very  solidly,  and  have  a  top  that  is  a  true  plane.  This 
will  be  found  very  convenient  on  which  to  build  some 
classes  of  patterns,  for  by  using  this  they  may  be  built 


FIG.  3. 

up  over  the  lines  laid  out,  as  is  sometimes  necessary.  In 
some  shops  this  laying  out  table  is  of  iron,  with  the  top 
planed  true. 

MEASURING  AND  LINING  APPLIANCES 

The  standard  of  length  used  by  mechanics  and 
engineers  in  the  United  States  is  the  English  yard.  The 
standard  for  reference  is .  the  "Troughton  Scale,'1  a 
bronze  bar  with  an  inlaid  silver  scale,  made  for  the  coast 
survey  of  the  United  States,  by  Troughton,  of  London. 
This  was  adopted  as  the  standard  by  the  Treasury 
Department  in  1832,  on  the  recommendation  of  Mr. 
Hassler,  who  was  at  that  time  the  superintendent  of  the 
United  States  Coast  Survey.  The  meter  has  since  been 
made  the  legal  standard ;  the  act  of  Congress  making  it 
such  was  passed  in  1877.  The  most  commonly  used 
measuring  appliance,  however,  is  what  is  known  as  the 
tWO  foot  rule.  This  is  a  strip  of  wood,  usually  boxwood, 
twenty-four  inches  long,  and  about  half  an  inch  wide. 
For  convenience  in  carrying,  it  is  jointed  so  that  it  can 


170 


WOOD    PATTERN    MAKING 


be  folded  into  two  or  four  folds.  These  rules  for  general 
wood  workers'  use  are  graduated  in 
sixteenths  of  an  inch  on  one  side  and 
eighths  of  an  inch  on  the  other.  The  bet- 
ter class  have  the  inside  of  each  leg  gradu  - 
ated  in  lOths  and  12ths  of  an  inch. 
(See  Fig.  4)*.  Another  form  of  rule  is 
what  is  known  to  pattern-makers  as  the 
Shrink  rule.  By  the  use  of  this  in 
pattern -making,  due  allowance  is  made 
in  the  pattern  for  the  shrinkage  that  will 
take  place  in  the  metal  of  the  casting. 
The  common  form  of  this  rule  is  a 
strip  of  boxwood,  one  and  one-fourth 
inches  wide,  and  twenty-four  and  one- 
fourth  inches  long.  It  is  divided  equally 
into  twenty -four  parts,  and  each  one  of 
these  parts  is  subdivided  as  in  the 
ordinary  two-foot  rule.  Another  meas- 
uring instrument  that  is  very  useful  to 
all  wood  workers,  especially  to  those 
having  much  laying  out  to  do,  is  the 
framing  Square.  This  is  made  of  steel, 
and  consists  of  two  flat,  thin  pieces  of 
that  metal,  united  at  right  angles  to  each 
other.  One  piece  is  two  inches  wide 
and  twenty -four  inches  long;  the  other 
one  and  one-half  inches  wide  and  seven- 
teen inches  long.  (See  Fig.  5).  These  are  graduated 
along  the  edges  of  the  flat  sides  the  same  as  the  two- 
foot  rules;  but  besides  these  graduations  there  are  others 


FIG.  4. 


APPENDIX 


running  through  the  center  of  the  sides. 
One  side  of  this  blade,  as  the  wider  side 
or  leg  is  called,  is  the  Essex  board 
measure,  which  is  very  useful  for  reading 
off  the  area  in  square  feet  of  a  board  or 
any  surface,  when  its  length  in  feet  and 
its  width  in  inches  are  known.  On  one 
side  of  the  short  leg,  or  tongue,  as  it  is 

called,  is  the  brace  measure  table.    This 

table  is  composed  of  sets  of  three  figures, 
two  of  which  are  the  lengths  of  two  sides 
of  a  right  angled  triangle,  the  other  the 
length  of  the  hypotenuse. 

A  try square  is j 

shown  by  Fig. 

6.    The  beam  I 

A  is  of  wood,' 

faced  with    a 

strip  of  brass   to  protect  it 

from    wear.     The  blade  B, 

at    right    angles      to      the 

beam,  is  of  steel.     In  some 

try    squares     the  blade    is 

graduated.  Some  try 
FIG.  5.  squares  are  made  entirely 
of  metal.  Fig.  7  represents  a  com- 
bination square;  the  blade  A  is 
raoveable  so  it  can  be  used  at  any 
length  on  either  side  of  the  head.  The 


FIG.  6. 


172 


WOOD   PATTERN    MAKING 


bevel,  Fig.  8,  sometimes  improperly  called  a  bevel  square, 
is  made  up  of  parts  which  are  similar  to  those  of  the  try 


FIG.  7. 

square,  and  have  the  same  names.     The  blade  is  adjust- 
able to   any  angle   with   the  beam,  and    when  set  the 


FIG.  8. 

thumb  screw  fastens  it.  The  size  of  both  square  and 
bevel  is  expressed  by  the  length  of  the  blade  in  inches. 
The  miter  Square  is  similar  to  the  try  square,  but  has  the 
blade  set  permanently  at  an  angle  of  45°  to  the  stock  or 
beam. 


APPENDIX 


173 


The  dividers  are  used  in  spacing  and  in  laying  out 
circles.  They  are  also  very  useful  for  laying  out  and 
transferring  angles.  One  way  of  using  them  for  this 
purpose  is  illustrated  at  Fig.  9,  which  shows  how  to  set 


FIG.  9 


a  bevel  at  an  angle  of  60°  and  120°.  To  do  this,  take  a 
board  that  is  planed  flat  and  one  edge  jointed,  that  is 
planed  straight.  Gauge  a  line  at  any  distance  from  this 
straight  edge;  from  any  point  on  this  line,  with  any 
radius,  use  the  dividers  to  make  the  arc  (B  C).  With 
same  radius  from  (B)  make  the  arc  (D).  Now  draw  a 
line  intersecting  these  two  points.  This  line  will  make 
an  angle  of  60°  with  the  edge  of  the  board  if  measured 
on  one  side,  and  120°  if  measured  on  the  other.  To  set 
the  bevel,  place  the  stock  or  beam  against  the  edge  of 
the  board  and  swing  the  blade  until  it  exactly  coincides 
with  the  line. 

Fig.  10  shows  the  usual  form  of  marking  gauge.    The 
steel  spur  should  be   filed    to  a  thin  cutting   edge ;  the 


174 


WOOD   PATTERN   MAKING 


long  way  is  to  stand  at  or  near  a  right  angle  to  the  beam 
in  such  a  way  that  when  pushed  along  with  the  left 
hand,  its  tendency  will  be  to  pull  the  gauge  onto  the 
piece  gauged.  The  square -shaped  piece  through  which 


FIG.  10. 


the  beam  slides  is  called  the  head.  The  graduations  on 
the  beam  are  not  to  be  depended  on  for  accurate  meas- 
urements. The  mortise  gauge  has  two  spurs ;  one  of  them 
is  moveable  on  the  beam  and  is  fastened  to  a  brass  slide 


FIG.  11. 


that  is  moved  back  and  forth  by  a  thumb  screw  at  the 
end  of  the  beam.     This  is  shown  at  Fig.  11. 


APPENDIX 


175 


CHISELS  AND  CHISEL -LIKE  TOOLS 
There  are  two  general  forms 
of  chisels  used  by  wood -work- 
ers, viz. ,  the  tanged  or  shank, 
and  the  socket.  These  terms 
refer  to  the  style  of  handle 
and  to  the  way  it  is  fastened 
to  the  chisel.  Almost  all  chis  - 
els  are  now  made  entirely  of 
steel.  The  tanged  form  is 
shown  by  Fig.  12 ,  and  is  called 
a  firmer  chisel.  It  has  a  long 
tongue  or  tang  which  is  driven 
into  the  handle,  the  bolster  (a) 
coming  up  against  the  end  of 
the  handle,  and  so  preventing 
its  being  driven  further  into 
it.  The  end  of  the  handle  is 
provided  with  a  ferrule  to  pre- 
vent splitting.  It  is  this  form 
of  chisel  that  is  usually  used 
by  workers  in  soft  woods,  such 
as  joiners  and  pattern-makers. 
The  better  quality  of  this 
form  of  chisel  has  beveled 
edges  as  shown.  The  other 
form,  known  as  the  socket 
firmer,  is  shown  at  Fig.  14. 
It  is  so  called  because  the 
handle  sets  into  a  socket  pro- 
vided for  it.  This  form  of 
chisel  is  more  generally  used 
FIG.  12  than  any  other,  as  all'classes 


FIG.    14 


176 


WOOD    PATTERN   MAKING 


FIG.  15 


of  wood-workers  except  join- 
ers and  pattern-makers  em- 
ploy it  almost  exclusively 
while  even  some  of  these 
prefer  this  kind  because  it  is 
stronger  than  the  tanged  firm- 
er. Socket  firmers  are  made 
of  different  weights  and  lengths 
for  different  kinds  of  work. 
The  better  grades  of  these  also 
are  made  with  beveled  edges. 
Gouges  have  blades  that  are 
curved  in  section  throughout 
their  length,  and  are  named 
and  used  like  chisels.  There 
are  two  general  forms  of  this 
tool,  viz:  the  inside  gouge, 
(Fig.  15)  and  the  outside  gouge 
(Fig.  16).  The  bevel  of  the 
first  is  ground  on  the  inside 
of  the  curve ;  that  of  the  other 
on  the  outside;  the  latter  is 
generally  the  more  useful. 
They  can  be  bought  with  the 
cross  section  of  three  different 
curvatures,  known  as  quick, 

middle,  and  flat  sweep;  this  is 

shown  at  Fig.  17,  which  rep- 
resents the  cutting  edge  of 
each.  The  sizes  of  all  gouges 
and  chisels  are  designated  by 
the  width  of  the  blade ;  a  two- 


FIG.  16 


APPENDIX 


177 


inch  chisel  or  gouge,  for  instance,  has  a  blade  that  is 
approximately  two  inches  wide.     They  are  made  in  sizes 


FIG.  17. 

as  follows:  From  one -eighth  inch  up  to  one  inch  by 
eighth  inches,  from  one  inch  to  two  inches  by  quarter 
inches. 


FIG.  18 

The  Drawing  Knife,  or,  as  it  is 

sometimes  called,  the  Draw  Shave, 

is  in  reality  a  very  wide  chisel,  but  is  not  used  in  the 
same  way.     It  is  shown  in  Fig.  18. 

SAWS 

The  saw  is  one  of  the  most  useful  and  effective 
wood-working  tools,  but  is  perhaps  the  most  difficult  to 
keep  in  good  order.  Saws  are  of  two  general  kinds ;  the 
rip  Saw  is  intended  to  cut  with  the  grain  of  the  wood ; 
the  croSS-CUt  Saw  is  used  for  cutting  across  the  grain.  A 
rip  saw  should  be  from  24  inches  to  26  inches  long  and 
should  have  from  four  and  a  half  to  six  teeth  to  the 
inch.  A  cross-cut  saw  for  bench  U  e,  is  called  a  panel 


178 


WOOD    PATTERN    MAKING 


19  FIG.  20          FIG.  21    FIG.  22 

Saw;  it  should  be  about  20  inches  long,  and  should  have 
from  eight  to  ten  teeth  to  the  inch.     A  full  sized  cross 


APPENDIX  179 

cut  saw,  called  a  hand  S3W,  is  26  inches  long  and  should 
have  from  seven  to  nine  teeth  to  the  inch,  (Fig.  19). 
The  back  Saw  (Fig.  20),  is  a  cross-cut  saw  with  a  very- 
thin  blade  and  fine  teeth;  the  blade  is  reinforced  with  a 
strip  of  brass  or  steel  along  its  back  edge,  hence  its 
name.  The  Key-hole  S3W  (Fig.  21),  is  a  narrow  bladed 
one  used  for  entering  small  holes  for  the  purpose  of  cut- 
ting a  short  distance  so  that  a  larger  saw  may  be  used, 
or  for  cutting  along  curved  lines.  Another  saw  that  is 
sometimes  used  for  similar  work  but  is  somewhat  larger, 
is  called  a  compass  S3W  (Fig.  22).  The  key  -  hole  and  the  com- 
pass saw  are  likely  to  be  used  both  across  the  grain  and 
with  the  grain,  and  are  therefore  filed  differently  from 
those  designed  especially  for  just  one  of  these  purposes. 

As  the  rip  saw  has  to  cut  or  sever  the  ends  of 
fibers  of  the  wood,  its  teeth  should  have  chisel -like 
points.  The  cross-cut  saw  has  to  also  sever  the  fibers  of 
wood,  but  in  a  different  way.  As  the  cutting  is  done 
across  the  fiber  of  the  wood,  it  requires  what  may  be 
called  a  scoring  of  the  fiber.  The  friction  of  the  other 
parts  of  the  teeth  on  the  wood  loosen  the  particles  cut  or 
separated,  and  carries  them  away  in  the  form  of  sawdust. 
The  size  of  the  teeth  are  governed  largely  by  the  size  of 
the  pieces  of  wood  to  be  sawn :  for  cutting  trees  into  saw 
logs  the  teeth  are  very  large ;  the  back  saw  has  very 
small  teeth,  as  it  is  used  for  cutting  comparatively  small 
pieces  of  lumber. 

In  the  actual  filing  of  saws  the  size  of  the  tooth  is 
determined  by  the  number  of  teeth  in  a  given  distance. 
The  size  of  its  teeth,  other  things  being  equal,  does  not 
help  or  hinder  the  smooth  cutting  of  a  saw.  For  a  rip  saw 
the  best  form  of  tooth  is  a  chisel -pointed  one;  the  best 
form  of  teeth  for  cross -cutting  effect  is  a  triangular  one. 


180  WOOD   PATTERN   MAKING 

These  two  forms  of  teeth  are  shown  in  Figs.   23  and  24. 


FIG.  23. 

The  different  angles  most  suitable  for  general  work  are 
also  indicated  in  the  same  figures,  Fig.  23  representing 
the  teeth  for  a  rip  saw  and  Fig.  24  the  teeth  for 
a  cross  cutting  saw.  These  should  be  varied  accord- 
ing to  the  kind  of  wood ;  they  should  be  less  acute  for 
hard  wood  and  more  acute  for  soft  wood.  The  kevhole 


FIG.  24. 

and  compass  saws  are  filled  with  a  combination  of  these 
angles. 

In  fitting  or  sharpening  a  saw  for  use,  there  are  four 
distinct  operations  to  be  performed :  1.  It  must  be  top- 
jointed;  that  is,  a  file  should  be  passed  along  the  tops  of 


APPENDIX  181 

the  teeth,  so  that  they  may  all  be  of  the  same  height  and 
extend  in  the  same  general  line,  the  line  being  a  slight 
curve.  2.  It  must  be  SCt;  that  is,  the  point  of  each  tooth 
is  bent  sidewise,  adjacent  teeth  being  bent  in  opposite 
directions.  3.  It  must  be  filed;  that  is,  the  individual 
teeth  must  be  filed  to  a  point.  4.  It  should  be  Side-jointed; 
that  is,  a  file  or,  preferably,  an  oil  stone,  should  be 
passed  along  the  side  of  the  teeth,  which  will  even  up 
the  set. 

BORING  TOOLS 

At  Fig.  25  is  shown  the  auger  bit.  This  is  the 
Russell  Jennings  pattern,  one  of  the  best  of  its  kind. 
Fig.  26  represents  what  is  called  a  square -hole  auger. 
The  boring  is  done  by  a  common  auger  bit  on  the  inside 
of  a  thin  shell,  which  is  square;  the  corners  are  sharp- 
ened, and,  as  the  extra  long  spur  or  screw  on  the  end  of 
the  auger  draws  it  into  the  wood,  these  square  corners 
cut  the  hole  made  by  the  auger  into  square  form. 
Fig.  27  is  the  Syracuse  drill  bit.  This  is  the  best  all- 
round  drill  for  wood  on  the  market.  Because  of  its  shape 
it  will  bore  in  any  direction  of  the  grain,  and  it  will  also 
operate  close  to  the  end  of  a  piece  without  splitting  it. 
If  it  becomes  dull  it  can  be  easily  sharpened.  At  Fig. 
29  is  shown  the  Expansive  bit,  one  of  the  most  useful 
boring  tools,  because  of  its  range  in  size.  It  can  be  set 
to  bore  any  sized  hole  within  its  range.  Two  sizes  can 
be  had,  one  boring  holes  from  one -half  inch  to  one  and 
one -half  inches,  and  the  other  seven -eighths  inch  to 
three  inches.  Fig.  28  shows  another  boring  tool  that  is 
very  handy,  especially  to  pattern-makers  and  to  others 
who  want  to  bore  holes  with  smooth  bottoms.  It  is  called 
the  Forstntr  bit.  It  has  no  spur  or  leading  screw,  so 
must  be  pushed  to  its  work.  Fig.  30  is  what  is  known 


182  WOOD   PATTERN   MAKING 


FIG.  25.  FIG.  26.  FIG.  26  (a). 

as  the  centre  bit.      It  is  very  convenient  for  boring  holes 


APPENDIX 


183 


FIG.  27.         FIG.  28.  FIG.  29.  FIG.  30. 

in  work  as  it  revolves  in  the  lathe.      The  central  spur  is 


184  WOOD   PATTERN   MAKING 

not  a  screw,  but  simply  a  triangular  point,  so  that  this 
bit,  like  the  last  one,  must  be  forced  to  its  work;  thus  it 
can  be  made  to  do  its  work  rapidly  or  slowly  as  the  job 
may  demand. 

In  providing  holes  for  screws  it  is  found  to  be  almost 
necessary,  especially  in  hard  wood,  to  countersink  the 
top  for  the  screw  head.  At  Fig.  31  is  represented  one 


FIG.  31. 

form  of  tool  used  for  this  purpose ;  it  is  called  a  COUntCF- 
Slnk.'  At  Fig.  32  is  shown  one  of  the  best  forms  of  what 
is  called  a  bit  brace  or  bit  Stock.  This  is  Fray's  rachet  bit 
brace.  For  general  use  the  auger  bit  is  preferred,  as 
when  sharp  it  will  cut  a  very  clean,  smooth  hole,  and  do 
it  rapidly.  In  boring  a  hole  through  a  piece  of  wood  with 
this  bit,  when  it  is  desired  to  leave  both  sides  smooth, 
care  should  be  taken  not  to  let  the  bit  go  clear  through 
from  one  side,  but  to  bore  just  far  enough  so  that  half  the 
length  of  the  screw  comes  through ;  then  remove  the  bit 
and  finish  the  hole  from  the  other  side.  Another  way 
this  may  be  done  is  to  clamp  a  piece  of  waste  wood  to  one 
side  of  the  piece  through  which  the  hole  is  to  be  bored. 

MISCELLANEOUS  TOOLS 

Hand  screw -drivers  are  of  several  shapes.  Fig. 
32  (a)  shows  one  very  common  form  which  is  a  very  good 
one  for  the  bench  worker.  Some  of  the  other  forms  are 
better  for  special  uses.  The  part  of  a  screw -driver  that 
enters  the  slot  of  the  screw  head  should  never  be  wedge- 
shaped;  otherwise,  when  force  is  applied,  the  tendency  is 


APPENDIX  185 

to  lift  it  from  its  place  instead  of  turning  the  screw.    The 
correct  shape  is  shown  at  one  side  of  Fig.  32  (a).     Brace 


^  FIG.  32.  FIG.  32  (a). 

screw -drivers  instead  of  having  a  handle,  are  provided 
with  a  shank  for  use  in  a  brace. 

A  hammer  and  a  mallet  are  needed  for  bench  work. 
The  Square  form  of  mallet  is  for  some  reasons  the  best. 


186  WOOD   PATTERN   MAKING 

What  is  known  as  the  daw  hammer  is  the  best  for  general 
bench  use.  The  nail-set,  though  small,  is  a  very  neces- 
sary tool  for  bench  work. 

The  miter    box,    one     form     of    which   is    shown 


FIG.  33. 

at  Fig.  33,  is  an  almost  indispensable  tool  for 
bench  workers.  It  is  the  most  useful  when  small 
pieces  of  irregular  outline,  such  as  mouldings,  have  to  be 
cut  to  a  miter  line,  in  the  case  of  a  picture  frame,  for 
instance.  The  word  miter,  when  used  without  a  qualify- 
ing word,  is  understood  to  mean  the  intersecting  line 
between  any  two  pieces  at  right  angles  to  each  other,  as 
the  diagonal  of  a  square.  When  pieces  are  to  be  mitered 
at  any  other  angle  than  45°,  the  angle  of  the  intersecting 
line  is  indicated  in  degrees;  for  instance,  a  sixty -degree 
miter. 

When  pieces  of  wood  have  to  be  held  together  tem- 
porarily, for  gluing  or  any  other  purpose,  some  form  of 
clamp  is  necessary.  The  form  shown  by  Fig.  34,  known 
as  hand  Screws,  are  the  most  used  by  pattern-makers.  In 


APPENDIX  187 

using  hand  screws  care  should  be  taken  not  to  force  the 
jaws  too  far  from  their  normal  parallel  position;  other- 
wise, the  threads  of  the  screws  may  be  stripped,  or  even 


&        \ w 

FIG.  34. 

the  screw  broken.  There  are  several  forms  of  iron 
clamps  on  the  market,  one  of  the  best  of  which  is  illus- 
trated by  Fig.  35.  These  are  sometimes  very  useful,  but, 


FIG.  35. 


all  things  considered,  hand  screws  are  the  best  for  bench 
work. 

A  grindstone  of  some  form  is  a  necessity  for  grind- 
ing the  cutting  edges  of  wood -working  tools.  It  is  to  be 


188  WOOD   PATTERN   MAKING 

selected  with  reference  to  its  grit ;  one  that  is  rather  fine 
and  soft  is  best.  A  power  grindstone  should  have  a 
speed  of  from  500  to  600  peripheral  feet  per  minute, 
depending  upon  its  diameter,  and  upon  the  steadiness 
and  accuracy  with  which  it  runs.  When  a  stone  throws 
water  from  its  face  it  is  running  too  fast  for  doing  good 
work  in  tool  grinding. 

PLANES   AND   PLANE -LIKE   TOOLS 

A  bench -worker's  "set"  of  planes  consists  of  four, 
the  jointer,  the  short  jointer  or  fore-plane,  the  jack- 
plane  and  the  smoothing -plane.  To  separate  these  into 
a  class  they  are  usually  spoken  of  as  surfacing  planes. 
These  differ  in  length  from  8  inches  in  the  smooth- 
ing plane  to  30  inches  in  the  jointer. 

The  jack-plane  is  the  first  one  used  in  planing  a 
rough  surface,  or  in  removing  surplus  material.  If  the 
surface  is  simply  to  be  smoothed,  then  the  smoothing  - 
plane  may  immediately  follow  the  jack-plane;  but  if  a 
true  surface  is  wanted  the  jack-plane  should  be  first  fol- 
lowed by  the  short  jointer,  and  then  by  the  jointer.  With 
the  last  named  plane  in  good  condition,  practically  a  true 
plane  may  be  made.  The  carpenter  or  joiner  would  call 
this  a  surface  that  is  OUt  of  Wind. 

To  test  a  surface  during  the  process  of  planing, 
"winding  sticks"  or  strips  are  used.  A  winding  stick  is 
a  strip  of  wood  of  wedge -like  cross -section  about  two 
inches  wide,  and  with  both  edges  straight  and  parallel 
to  each  other.  Two  of  them  are  needed  to  test  a  surface, 
one  being  placed  near  each  end  of  it.  After  setting  them 
on  the  surface  exactly  parallel  to  each  other  the  operator 
should  sight  across  from  one  to  the  other.  As  the  eye 
is  lowered,  if  the  one  farther  away  is  lost  sight  of  all  at 


APPENDIX  189 

once,  the  surface,  if  straight  between  the  points  on  which 
the  strips  set,  is  a  true  plane,  and  is  said  to  be  OUt  of  wind. 
If  the  farther  one  does  not  disappear  all  at  once  but  the 
top  edges  appear  to  cross  each  other,  then  the  surface  is 
not  a  true  plane,  and  is  spoken  of  as  a  winding  surface 
or  in  Wind.  If  the  surface  is  in  wind,  notice  which  ends 
of  the  winding  sticks  are  the  higher.  Then  if  a  true 
surface  is  wanted,  plane  off  some  of  the  surface  at  the 
points  under  the  higher  ends,  and  test  again.  In  order 
to  obtain  the  greatest  advantage  to  be  gained  from  the 
use  of  winding  sticks,  they  should  be  considerably  longer 
than  the  width  of  the  surface  to  be  tested.  Thus  the 
width  of  the  surface  is  exaggerated,  which  is  one  object 
sought  in  using  these  strips.  The  blades  of  two  framing 
squares  answer  admirably  for  this  purpose.  The  use  of 
these  surfacing  planes  should  be  thoroughly  acquired,  so 
that  the  surfaces  of  any  piece  or  pieces  to  be  used  for  the 
construction  of  any  object  may  be  readily  and  correctly 
planed.  As  plane  surfaces  are  to  a  degree  the  founda- 
tion for  the  future  work  to  be  done  on  them,  it  is  very 
essential  that  they  should  be  correct;  if  otherwise,  poorly 
fitting  joints  will  result.  Good  work  cannot  be  done  if 
the  working  faces  are  incorrectly  planed. 

The  cutting  irons  of  all  these  planes  are  true  cutting 
wedges  of  different  widths,  the  width  varying  with  the 
length  of  the  plane.  To  each  of  these  wedges  is  added  a 
supplementary  iron  called  a  Cap  or  back  iron,  which  is 
placed,  as  its  name  indicates,  on  the  back  of  the  cutting 
iron,  thus  making  it  a  double  iron.  The  purpose  of  the 
back  iron  is  to  break  the  shaving  as  it  is  made  by  the 
cutting  wedge. 

The  exact  way  in  which  this  is  done  can  be  explained 
better  with  a  cut  than  with  words  alone.  Fig.  36  shows 


190 


WOOD   PA.TTERN    MAKING 


how  the  wedge  acts  as  a  single  iron.  At  Fig.  37  is  shown 
the  double  iron  and  the  effect  of  the  back  iron  on  the 
shaving.  As  the  shaving  is  cut  and  bent  by  the 


FIG.  36. 

wedge,  its  tendency  is  to  follow  the  back  of  the  plane 
iron  as  at  A,  Fig  36.  As  seen  at  A,  Fig.  37,  the  back 
iron  prevents  this,  by  changing  its  course  and  breaking 
it  before  it  has  time  to  split  down  into  the  wood. 
The  single  iron  does  very  good  work  so  long  as  the 
grain  is  favorable,  but  when  it  comes  to  a  place  on  the 


FIG.  37. 

board  that  is  cross-grained,  as  at  B,  the  shaving  will 
split  ahead  of  the  cutting  iron  and  leave  the  surface 
rough. 


APPENDIX  191 

Fig.  38  shows  the  wood  plane  and  and  the  advantage 
of  a  narrow  mouth,  which  the  iron  plane  shown  by  Fig. 
37  lacks.  This,  too,  changes  the  direction  of  the  shav- 
ing. It  has  also  the  advantage  that  it  aids  the  plane  in 
doing  smooth  work  at  a  spot  where  the  lumber  is  cross- 
grained,  for  the  narrow  mouth  holds  down  the  wood 


FIG.  38. 

immediately  in  front  of  the  cutting  iron,  and  so  prevents 
its  being  torn  up  before  it  is  cut.  This  is  one  of  the 
advantages  that  the  wood  plane  has  over  the  iron, 
another  being  the  comparative  ease  of  working.  Still, 
when  everything  is  considered,  iron  planes  are  the  best. 
Their  principal  advantage  is  that  they  will  not  warp  or 
appreciably  wear ;  consequently  the  face  or  Sole  of  the 
plane  is  always  a  true  plane. 

The  cutting  edge  of  plane  irons  should  not  be 
straight  but  slightly  curved.  For  the  jack-plane  this 
curve  ought  to  be  much  quicker  than  for  the  other  planes. 
The  jack-plane  is  frequently  used  for  removing  very 
thick  shavings  and  if  the  iron  were  straight,  it  would 
tear  out  a  rectangular  groove  for  the  whole  width  of  the 
iron.  This  would  be  very  likely  to  clog  the  plane  and 
would  also  consume  much  more  force  than  if  the  edge 


192  WOOD    PATTERN    MAKING 

was  curved.  In  a  given  time  with  a  given  amount  of 
force  applied,  much  more  wood  can  be  removed  if  the 
iron  is  curved  than  if  it  were  straight. 

Theoretically,  the  outline  of  the  cutting  edge  for  the 
jointer  and  smoothing -plane  irons  should  be  straight  in 


FIG.  39 

order  to  produce  a  straight  flat  surface,  but  in  practice 
this  is  not  the  case.  So  for  these  irons  the  corners 
should  be  slightly  rounded,  or,  what  is  better,  be  slightly 
curved,  but  the  radius  of  the  curve  should  be  much 
larger  than  for  the  jack-plane  iron. 

Fig.  39  shows  the  iron  jack-plane,  the  other 
three  of  the  set  are  the  same  shape.  Fig.  40  shows  one 
form  of  the  block-plane.  The  principal  use  of  this  plane 


FIG.  40 


is  to  smooth  end  grain.  The  angle  at  which  the  iron  is  set 
in  this  plane  is  much  smaller  than  that  of  other  planes. 
This  being  the  case,  the  iron,  which  is  always  a  single 


APPENDIX  193 

one,  is  inverted.  If  if  were  not,  the  angle  of  the  cutting 
wedge  would  have  to  be  so  small  that  it  would  not  stand 
up  to  the  work.  To  prevent  this  plane  from  breaking 
over  the  corners  of  the  wood,  when  being  used  on  the 
end  of  a  board  or  other  piece,  another  piece  should  be 
placed  back  of  the  one  being  planed.  If  the  board  is  of 


FIG.  41 


considerable  width  the  plane  may   be  worked  both  ways 
and  not  carried  clear  across. 

Another  plane  that  is  very  useful  to  wood-workeis 
is  shown  at  Fig.  41,  called  a  rebate  plane.     The  iron  is 


FIG.  42 

set  askew  in  the  plane  and  extends  the  whole^WJdth]of  the 
face.  It  is  used  for  cutting  a  rectangular  space^called  a 
rebate,  into  the  corner  of  a  piece  of  wood.  This  word 
has  been  corrupted  into  "rabbit." 


194  WOOD    PATTERN    MAKING 


Another  plane -like  tool  is  illustrated  by  Fig.  42. 
This  is  the  carpenter's  plow.  Its  principal  use  is  the 
cutting  of  rectangular  grooves  into  wood  parallel  with 
the  grain.  It  is  adjustable  and  can  be  set  to  cut  the 
groove  at  any  distance  from  the  face  of  a  board.  Irons 
of  different  widths  are  supplied  so  that  grooves  of  any 
width  and  depth  may  be  cut. 

A  plane  called  a  dado  plane,  shown  at  Fig.  43,  is 


FIG.  43 

used  for  cutting  rectangular  grooves  CfOSSWays  of  the 
grain.  Its  iron  is  set  askew.  It  has  a  depth  gauge  to 
regulate  the  depth  of  the  groove. 

Combination  planes  made  of  metal,  which  may  be  used 
in  the  place  of  the  plow,  dado,  matching  planes,  beading 
planes,  etc.,  are  on  the  market  and  some  of  them  are  very 


FIG.  44 

serviceable  tools.  Spoke -shaves  have  the  action  of  planes 
but  are  not  usually  classed  with  them.  A  simple  form 
is  shown  at  Fig.  44.  It  has  a  very  small  face  which 
adapts  it  for  use  on  irregular  surfaces.  Another  form 
which  is  very  serviceable  for  quite  small  curves  is  shown 
at  Fig.  45.  There  are  several  other  forms  of  planes  in 


APPENDIX 


195 


use,  but  most  of  them  are  designed  for  specific  uses, 
and  are  not  commonly  used  by  the  pattern- 
maker. 

There  is  one  plane,  however,  that  is  used 
by  pattern-makers,  and  which  is  mentioned 
in  the  body  of  this  work,  but  represented  there 
in  the  wooden  form,  that  should  be  noticed 
here ;  that  is  the  latest  form  of  iron  core  box 
plane,  and  is  represented  by  Fig.  54. 


FIG.  54 

CUTTING    WEDGES 

From  the  wood -worker's  point  of  view,  the  chisel  is 
the  typical  Cutting  tool.  It  has  two  operations  to  perform 
when  in  action,  viz.:  cutting  the  fiber  of  the  wood,  and 

breaking,  crushing  to  one  side,  or  bending  the  wood  out  of 

the  way,  so  that  the  cutting  edge  may  go  on  with  its 
work.  Every  cutting  tool  is  a  wedge,  more  or  less 
acute.  To  widen  the  cut  the  wood  must  be  bent;  this 


196  WOOD    PATTERN    MAKING 

the  cutting  wedge  of  the  plane  does,  and  thus  forms  a 
shaving.  The  chisel,  when  driven  into  the  wood,  as  in 
cutting  a  mortice,  crushes  the  wood  and  so  widens  the 
cut.  When  the  wedge  is  driven  in  parallel  with  the 
grain,  the  fibers  are  pressed  apart, the  cut  is  widened  and 
the  wood  split.  It  can  be  demonstrated  that  much  less 
force  is  required  to  carry  the  wedge  forward  when  first 
entering  the  cut  than  after  it  has  extended  into  the 
material  for  some  distance.  It  is  reasonable,  therefore, 
to  suppose  that  the  larger  part  of  the  force  applied  to 
form  a  shaving  or  chip,  is  consumed  in  this  bending  or 
crushing,  and  a  very  small  part  by  the  actual  cutting  of 
the  fiber  of  the  wood.  A  very  acute  angled  wedge  will 
do  a  given  amount  of  work  with  less  force  than  one  not 
so  acute.  But  the  one  with  the  larger  angle  will  do  the 
actual  cutting  as  easily  as  the  other.  The  angle  of  the 
wedge  has  very  little  to  do  with  the  force  required  to  do 
the  cutting,  at  least  up  to  any  angle  that  would  or  could 
be  used  for  cutting  wood.  The  acuteness  is  limited  only 
by  the  strength  of  the  steel,  so  it  must  vary  as  the  kind  of 
work  and  material  varies.  A  more  acute  one  may  be  used 
for  soft  wood  than  for  hard  wood.  And  again,  a  larger 
angled  wedge  is  needed  in  a  chisel  that  is  to  be  used  or 
driven  to  its  work  with  the  mallet  than  in  one  that  is  to 
be  used  with  the  hands  only. 

If  it  was  insisted  on  that  a  cutting  wedge  should 
always  have  its  maximum  of  delicacy,  it  would  necessi- 
tate that  the  angle  be  changed  for  almost  every  shaving 
or  chip  made.  This  would  be  impracticable,  so  that  the 
results  of  the  experience  of  wood -workers  may  be 
expressed  as  follows:  "Make  the  cutting  wedge  as 
acute  as  the  metal  will  allow  without  breaking,  when 
fairly  used."  The  angle  of  the  wedge  for  all  wood- 


APPENDIX  197 

cutting  tools  for  general  use  should  be  from  25°  to  30°. 

The  sharpening  of  a  cutting  wedge  requires  con- 
siderable care  and  skill,  if  it  is  required  to  do  first-class 
work  with  it.  If  the  chisel  or  other  edge  tool  is  new,  or 
very  dull,  it  must  first  be  ground.  This  is  best  done  on 
a  medium  grit,  soft  grindstone.  Emery  wheels  are  largely 
taking  the  place  of  grindstones  for  this  purpose.  Greater 
care  is  necessary  in  the  use  of  emery  wheels  than  with 
grindstones  for  grinding  WOOd-WOrking  tools,  for  the 
wedge  being  thin,  the  temper  of  the  steel  is  very  liable 
to  be  drawn  by  the  heat  generated  by  the  friction.  In 
grinding  a  cutting  wedge,  the  grindstone  should  revolve 
toward  the  Cutting  edge.  The  correct  position  in  this 
regard,  and  also  to  produce  the  best  angle  for  general 
use  is  shown  in  Fig.  46.  Plenty  of  water  must  be  kept 


FIG.  46. 

on  the  stone  during  the  process  of  grinding.  The  water 
serves  two  purposes;  one  is  to  reduce  the  temperature 
generated  by  friction,  the  other  to  keep  the  stone  clean 
or  to  carry  off  the  particles  of  sand  and  metal  loosened  in 
the  process  of  grinding.  The  surface  produced  by  the 
grinding  is  called  the  bevel, 

As  the  coarse  grit  of  the  grindstone  will  not  produce 
a  clean,  smooth  cutting  edge;  the  tool  will  have  to  be 
Whetted.  This  is  done  on  an  oil  stone,  either  natural  or 
artificial.  The  latter  kind,  if  made  by  a  reliable  firm,  is 
the  best,  as  it  wears  more  evenly.  The  tool,  while  held 


198  WOOD  PATTERN  MAKING 

in  such  a  position  that  the  heel  of  the  wedge  does  not 
quite  touch  the  stone,  should  be  carried  back  and  forth 
along  the  whole  length  of  it,  care  being  taken  not  to  give 
the  tool  a  rocking  motion,  which  would  produce  a  curved 
instead  of  a  straight  line.  This  operation  should  be  con- 
tinued until  a  slight  wire  edge  is  produced  on  the  back, 
as  the  straight  side  is  called.  The  wire  edge  must  be 
removed  in  order  to  produce  a  sharp  edge  that  will  cut 
smoothly.  To  do  this,  lay  the  tool  on  its  back,  flat  on  the 
oil  stone,  and  give  it  a  few  light  strokes  toward  the  edge. 
Great  care  should  be  taken  not  to  raise  the  handle  of  the 
tool,  as  that  would  bevel  this  side  of  the  wedge  and 
impair  the  proper  working  of  the  tool.  There  are  two 
tests  that  may  be  used  to  determine  if  the  edge  is  sharp. 
One  by  the  eye,  the  other  by  the  sense  of  touch.  If  a 
sharp  edge  is  examined  by  the  eye,  it  will  be  noticed  that 
a  dull  line  appears  where  the  edge  is.  If  the  edge  is  not 
sharp,  a  bright  line  will  be  seen.  The  more  dull  the 
tool  is,  the  larger  the  bright  line  will  appear.  To  test  by 
the  sense  of  touch,  place  the  thumb  or  finger  on  the  edge, 
and  try  to  move  it  along  the  edge.  If  it  is  not  sharp,  no 
difficulty  will  be  found  in  doing  this.  If,  however,  the 
edge  is  sharp,  a  clinging  or  pulling  sensation  will  be  felt. 
The  best  test,  however,  is  to  cut  wood  in  the  same  direc- 
tion as  the  work  to  be  done.  If  the  surface  cut  is  smooth 
and  glossy,  the  tool  is  sharp.  If  the  tool  is  dull  it  will 
cut  a  surface  that  is  rough  and  dull  to  both  touch  and 
sight. 

LAYING  OUT  WORK 

The  production  and  location  of  lines  is  one  of  the 
most  important  parts  of  wood  work,  as  of  all  mechanical 
work,  in  the  production  of  work  of  a  definite  size  and 
shape.  Any  carelessness  in  this  direction  will  always 


APPENDIX  199 

make  itself  manifest  in  the  finished  product.  This  is  so 
much  the  case  that  one  who  is  habitually  careless  in  this 
regard  seldom  makes  a  good  mechanic.  L,et  it  be  under- 
stood at  the  outset  that  a  scratch  is  not  a  line,  and  that 
patience  and  accuracy  in  the  making  and  locating  of  lines 
is  one  of  the  first  requisites  to  success  in  all  mechanical 
manipulations,  and  in  the  production  of  all  articles  made 
by  mechanical  processes. 

The  tools  used  for  marking  lines  are  four, — the 
chalk  line,  pencil,  gauge  and  knife.  For  bench  work  the 
knife  and  gauge  are  the  most  used.  The  knife  is  used 
for  marking  across  the  grain,  and  should  have  a  sharp 
point  so  that  it  will  cut  into  the  wood,  not  merely  scratch 
it.  In  making  a  mark  where  a  cut  is  to  be  made  with  a 
saw,  the  lines  may  to  advantage  be  cut  y32  of  an  inch 
deep.  The  gauge  is  the  best  implement  for 
marking  lines  lengthwise  of  the  grain.  A  great  deal 
more  might  be  said  about  this  part  of  wood -working, 
—laying  OUt  work,  as  it  is  usually  called— but  space 
forbids. 

PATTERN   TURNING 

The  term  WOOd  turning  is  generally  understood  to 
mean  the  making  or  forming  of  any  circular  form 
required  of  wood,  while  revolving  at  a  high  rate  of  speed 
in  some  form  of  lathe.  Wood  turning  is  done  in  two  dis- 
tinct ways ;  first,  along  or  parallel  with  the  grain ;  and 
second,  across  the  grain,  or,  as  it  is  sometimes  called, 
plankwiSC.  Wood  turning  may  be  divided  into  two  kinds, 
cabinet  turning,  by  which  balusters  and  other  decorative 
articles  are  produced ;  and  pattern  turning,  a  method  used 
by  pattern-makers,  by  which  the  many  circular  forms 
required  in  that  trade  are  made.  The  same  tools  are  used 
on  both  kinds  of  turning,  but  the  processes  are,  in  some 


200 


WOOD    PATTERN    MAKING 


respects,  quite  different.  The  cabinet  turner  is  more 
concerned  as  to  the  beauty  of  outline  and  finish  than 
with  exact  size,  and  uses  methods  that  will  accomplish 
these  results.  The  pattern  turner,  on  the  other  hand, 
must  have  exactness  in  size,  the  finish  being  a  secondary 
matter.  This  being  the  case,  whereas  the  cabinet  turner 
actually  cuts  the  fibers  of  the  wood,  the  pattern  turner 
uses  what  is  called  a  Scraping  cut  for  most  of  his  work. 
A  common  form  of  turner's  lathe  is  shown  by  Fig.  47. 


FIG.  47. 


In  the  figure,  A  is  the  bed,  B  is  the  head  Stock,  C  is  the 
tail  Stock,  D  is  the  Step  cone  pulley  on  which  the  belt  runs 
that  drives  it  and  the  spindle  G,  and  with  it  the  driving  OF 


APPENDIX  201 

lork  center,  which  in  turn  drives  the  work.  The  fork 
center  is  driven'into  a  tapered  hole  in  the  spindle,  and  is 
held  by  friction  only.  In  the  tail  stock  is  the  back  Center, 
H.  At  F  is  the  tool  or  hand  rest. 

Fig.  48  shows  an  enlarged  view  of  the  most  common 


FIG.  48. 

form  of  fork  chuck.  The  fork  chuck  at  the  left  hand, 
and  the  back  center  at  the  right,  make  up  the  common 
appliance  for  holding  work  in  the  lathe,  when  the  turn- 
ing is  to  be  done  lengthwise  or  parallel  with  the  grain.  For 
turning  plankwJSC  or  across  the  grain,  there  are  several 
kinds  of  Chucks  employed,  the  simplest  being  the  SCFCW 
ChircK,  shown  at  Fig.  49,  in  two  forms.  A  face  plate  is 
shown  in  the  center  of  Figs.  62  and  63,  pages  122  and 
123,  and  a  chuck  for  large  work  at  Fig.  62,  and  one  at 
Fig.  63  adapted  to  still  larger  work.  The  pieces  shown 
at  A,  Fig.  62,  are  not  necessary,  but  they  area  great  con- 
venience when  it  is  required  to  hold  work  on  the  chuck 
with  hand  screws,  as  in  gluing  up  work.  If  the  chuck 
has  such  a  rim,  the  hand  screws  may  all  be  set  open  the 
same  distance,  and  therefore  quickly  applied,  which  is 
necessary  when  using  glue.  For  small  work,  a  chuck 


202 


WOOD    PATTERN    MAKING 


may  be  simply  a  disk  of  wood.  Each  chuck  must  have  a 
face  plate  fastened  to  it  during  its  use.  There  are  several 
different  ways  of  fastening  work  to  these  chucks,  gener- 
ally determined  by  its  size  and  shape.  It  may  be  fastened 
with  screws  or  nails,  it  may  be  glued  directly  to  the 


FIG.  49. 

chuck,  and  it  maybe  glued  to  paper  already  glued  to  the 
chuck.  When  this  last  way  is  used,  the  work  may  be 
taken  off  without  damaging  it,  because  the  paper  will 
split.  When  it  -is  glued  directly  to  the  chuck  it  will 
have  to  be  cut  off,  so  this  way  is  not  usually  employed 
except  for  patterns  of  thin  (TOSS  Section,  such  as  pulley 
rims,  that  can  be  easily  cut  through.  Besides  these  plain 
chucks,  several  other  forms  are  in  use  for  special  work, 
one  of  which  is  represented  by  Fig.  50,  and  is  called  a 
Cup  chuck.  One  of  its  uses  is  to  hold  a  sphere  in  the  lathe 
while  it  is  being  given  the  finishing  touches.  Some  of 
the  specific  uses  of  these  appliances  are  described  in  the 
body  of  this  volume. 


APPENDIX  203 

Not  many  different  forms  of  tools  are  required  for 
pattern  turning,  but  quite  a  number  of  different  sizes  of 
the  same  form  are  needed.  The  first  to  be  noticed  is  the 
turner's  gouge,  shown  by  Fig.  51,  and  the  skew,  or  tum- 


FIG.  50. 

ing  Chisel,  illustrated  at  Fig.  52.  These  two,  in  their  dif- 
ferent sizes  are  the  only  tools  used  by  the  turner  for  cutting 
the  fiber  of  the  wood .  All  the  others  are  really  scraping  tools , 
and  do  not  actually  cat.  The  other  tools  most  used  for 
pattern  turning  are  illustrated  by  Fig.  53.  At  A  is  shown 
a  pair  of  the  ordinary  scrapers,  the  tool  most  used  on 
flat  and  convex  surfaces.  At  B  is  shown  the  round -nosed 
scraper,  used  for  concave  surfaces;  several  sizes  of  this 
are  needed  for  a  medium  range  of  work.  At  C  the  ordin- 
ary parting  tool  is  shown.  This  is  a  very  useful  tool  for 
working  wood  plankwise ;  its  special  form  gives  Clearance 
in  whatever  position  it  may  cut  the  wood.  The  tool 
shown  at  D  is  also  a  very  good  tool  for  turning  wood 
across  the  grain,  especially  if  a  large  amount  of  wood  is 
to  be  removed.  This  it  will  do  rapidly  and  easily.  It  is 

called  a  diamond  point  parting  tool.     At  E,  in  Fig.  48,  is 

shown  a  straight  scraper,  which  is  very  useful  for  finish- 


204  WOOD    PATTERN    MAKING 

A 


FIG.  52. 


FIG.  51. 


ing  large  straight  surfaces.  It  is  made  from  a  firmer 
chisel  that  is  worn  too  short  for  its  original  use.  Indeed, 
worn-out  chisels  of  this  type  make  first-class  turner's 
scrapers.  All  the  scraping  tools,  except  those  shown  at 
A  and  D,  may  be  made  of  these  and  will  serve  their  pur- 
pose admirably.  The  two  noted  above  are  sometimes 
needed  longer  than  the  others,  and  are  better  if  made  of 
heavier  stock. 


APPENDIX 


205 


The  art  of  turning  can  be  learned  by  the  student  only 
in  the  same  way  that  any  other  mechanical  trade  or  craft 
is  learned,  i.  e.,  by  actually  doing  the  work  and  perform- 


D 


FIG.  53. 

ing  the  operations  involved  in  the  practice  of  that  art, 
This  being  the  case,  only  a  few  simple  directions  will  be 
given  here.  These  directions  may  best  be  given  by 
explaining  the  operations  that  must  be  performed  in  turn- 
ing a  cylinder.  The  first  thing  to  be  done  is  to  saw 
out  the  stock  square,  with  the  sides  about  one -eighth 
inch  larger  than  the  diameter  of  the  proposed  cylinder. 
Next  make  a  center  mark  on  each  end  by  drawing 
diagonal  lines  across  it ;  at  these  points  the  lathe  centers 
are  to  enter.  To  set  the  work  in  the  lathe,  place  one  end 
against  the  driving  center,  or  head  center,  and  with  a 
hammer  or  mallet  drive  on  the  other  end  until  the  chuck 
has  entered  the  wood  far  enough  to  revolve  the  wood 
against  the  tools ;  now  while  holding  the  right  hand  end 
in  the  left  hand,  slide  up  the  tail  stock  with  the  right 
hand  until  its  center  touches  the  wood,  and  clamp  it  to 
the  bed.  With  the  handle  connected  with  the  tail  center, 
push  the  center  into  the  right  hand  end  far  enough 


206 


WOOD   PATTERN   MAKING 


to  make  it  secure.  Adjust  the  tool  rest  so  it  will  just  clear 
the  corner  of  the  piece  when  revolving.  It  is  a  good 
plan,  before  applying  the  power,  to  give  the  belt  a  pull 
with  the  hand  to  ensure  that  everything  is  clear. 

The  gouge  is  the  first  tool  to  be  used  on  this  kind  of 
turning;  the  cutting  done  by  it  at  this  stage  of  the 
work  is  termed  the  roughing  cut.  The  gouge  is  so  held 
that  a  center  line  through  the  tool  will  be  perpendicular 
to  the  axis  of  the  work.  The  bevel  of  the  cutting  wedge 
should  be  held  tangent  to  the  proposed  cylinder,  and 
rolled  on  its  side  as  indicated  by  Fig.  55  at  A.  The 


FIG.  55. 

direction  in  which  the  tool  is  moving  is  indicated  by  the 
arrow  in  each  case.  In  this  position  the  angle  of  the  cut 
will  be  about  25°  to  30°  with  the  axis  of  the  cylinder, 
which  is  the  best  for  this  kind  of  turning.  The  gouge  is 
used  by  good  turners  for  doing  a  very  large  proportion  of 
the  work  on  plain  cylindrical  and  concave  surfaces. 

Plain  cylindrical  and  convex  surfaces  are  finished 
with  the  turning  or  skew  chisel,  the  only  other  cutting 
tool  used  by  turners.  Its  use  requires  a  great  deal  of 
skill  on  the  part  of  the  operator.  On  account  of  its  shape 


APPENDIX  207 

it  has  a  great  tendency  to  rip  or  tear  into  the  work  with 
its  long  corner.  One  reason  for  its  so  doing  lies  in  the 
fact  that  it  cannot  be  laid  flat  on  the  tool  rest,  but  must  be 
supported  as  shown  at  Fig.  56,  and  at  A  and  B,  Fig.  57. 


FIG.  56. 

This  being  the  case,  the  keeping  of  the  edge  of  the 
chisel  in  its  proper  position  and  angle  with  the  work 
depends  entirely  on  the  skill  of  the  workman.  This  skill 
cannot  be  imparted,  but  some  suggestions  can  be  given 
that  will  aid  the  student  in  acquiring  it.  Do  not  let  the 
chisel  cut  above  the  central  point  of  the  length  of  the 
cutting  edge,  that  is  at  D,  in  Fig.  56.  Retain  a  firm  grip 
on  the  handle  with  the  right  hand. 

The  bevel,  like  the  gouge,  should  be  laid  on  the 
cylinder  exactly  tangent,  and  held  so  that  the  handle  is 
perpendicular  to  the  axis  of  the  cylinder.  As  one  corner 
only  of  the  chisel  touches  the  rest,  it  is  very  difficult  to 
keep  it  in  its  correct  position.  If  the  bevel  is  exactly 
tangent,  it  will  not  cut;  so  it  must  be  tipped  enough  to 
be  tangent  to  a  circle  slightly  smaller  than  the  one 
already  cut.  This  is  best  done  by  simply  rolling  the 
chisel  with  the  hand  until  it  cuts  a  shaving  of  the  desired 
thickness.  As  a  general  thing,  the  cylinder  should  be 
cut  almost  to  size  with  the  gouge,  leaving  only  a  shaving 
or  two  to  be  removed  by  the  chisel. 


208 


WOOD    PATTKRN    MAKING 


Pattern-makers  do  almost  all  this  finishing  with  a. 
scraper  like  E,  of  Fig.  48.  The  position  of  this  tool  for 
scraping  plain  cylindrical  surfaces  is,  as  shown  in  Fig, 
58,  exactly  on  the  diameter  of  the  cylinder.  The  cutting 
of  shoulders  like  those  in  Fig.  57,  and  also  the  square 


FIG.  57. 

ends  of  the  same  figure  is  done  with  a  skew  chisel.  The 
chisel  is  held  as  there  shown,  that  is,  at  a  slightly 
larger  angle  than  the  one  at  which  it  is  sharpened ;  so  no 
part  of  the  Cd^C,  except  the  extreme  point,  should  touch 
the  wood.  The  ends  of  nearly  all  plain  cylindrical  pat- 
terns have  to  be  made  convex.  To  make  them  so,  the 
chisel  may  be  held  with  the  center  line  of  its  length  per- 
pendicular with  the  axis  of  the  cylinder,  while  at  the 
same  time  the  edge  of  the  chisel  is  perpendicular.  For 
making  other  forms  in  the  lathe,  the  tools  shown  in  Fig.. 
53  are  used.  These  are  all  scraping  tools. 

SHARPENING   LATHE   TOOLS 

The  cutting  wedges  of  the  turning  gouge  and  the- 
turning  chisel  are  sharpened  in  the  same  way  as  other 
cutting  wedges.  The  wedges  for  soft  wood,  however,, 
should  be  more  acute  than  the  bench  chisel  for  general 
work.  The  wedge  of  turning  chiselsfpr,u.$ejn  soft.wood^ 


APPENDIX  209 

may  be  ground  to  an  angle  of  20°,  and  must  be  kept  very 
keen  if  good  work  is  to  be  done.  The  roughing  gouge 
should  have  a  wedge  of  30°.  The  scraping  tools  should 
have  wedges  of  about  45°,  and  be  ground  on  one  side 
only,  as  shown.  As  the  cutting  edge  of  the  scraping 


FIG.  58. 

wedge  is  on  the  side  instead  of  on  the  end,  as  in  the 
cutting  wedge,  it  requires  a  different  treatment  to  secure 
the  best  results.  After  sharpening  the  chisel  in  the 
usual  way,  place  it  on  the  oil  stone  on  its  bevel,  and, 
while  holding  it  in  that  position,  give  it  two  or  three 
strokes  parallel  with  the  back.  This  will  give  a  con- 
tinuous wire  edge,  which  is  just  what  is  needed.  Push- 
ing the  chisel  back  and  forth  in  the  usual  way  also  pro- 
duces a  wire  edge,  but  it  is  a  serrated  one,  and  therefore 
is  quickly  dulled. 

TOOLS  FOR  MEASURING  TURNED  WORK 

The  special  tools  for  measuring  turned  work  are 
shown  at  Figs.  59  and  60.  The  former  is  the  outside  caliper, 
the  latter  the  inside  caliper.  The  outside  caliper  is  used 
for  measuring  the  outside  of  round  or  cylindrical  work, 


210  WOOD    PATTERN    MAKING 

the  inside  caliper  for  measuring  holes  and  cavities  either 
cylindrical  or  of  other  forms.  The  outside  caliper  may 
be  used  when  the  work  is  revolving,  provided  it  is  very 


FIG.  59.  FIG.  60. 

nearly  cylindrical.  The  inside  caliper  should  not  be 
applied  to  work  that  is  revolving,  as  it  is  likely  to  be 
caught  by  the  wood  and  jerked  out  of  the  hand.  The 
common  two -foot  rule  is  used  for  measuring  along  a 
cylinder,  when  the  caliper  would  be  unhandy.  When  a 
number  of  pieces,  balusters  for  instance,  are  to  be  made 
alike,  a  special  measuring  device  is  usually  made  use  of 
by  turners.  It  consists  of  a  light  stick  of  wood  with 
sharpened  wire  brads  driven  into  it  at  certain  points  along 


APPENDIX  211 

its  length, where  the  deeper  cuts  are  to  be  made.  After  the 
piece  is  turned  down  roughly  to  size,  this  scriber,  as  it  is 
called,  is  laid  on  the  tool  rest  in  such  a  way  that  the 
sharpened  nails  will  just  touch  the  cylinder  as  it  revolves, 
thus  making  a  line  around  it  where  it  is  to  be  cut.  This, 
of  course,  saves  time,  for  the  reason  that  the  lines  are  all 
made  at  once,  and  the  distances  between  them  are  meas- 
ured at  the  same  time  for  all  the  pieces.  It  is  not  often, 
however,  that  the  pattern-maker  has  any  use  for  this 
device,  as  his  work  is  seldom  duplicated. 


INDEX 


Amount  of  shrinkage  in  small 

patterns,  17. 

Annular  patterns,  61,  140. 
Angles,   173. 
Arms  of  wheels,  99. 


B 


Bevel  gear  patterns,  120. 
Bit,  sqr.  hole,  182. 

—  auger,  182. 

—  center,  183. 

—  drill,  183. 

—  brace,  185. 

—  countersink,  184. 
Black  varnish,  26. 
Boxing  up  patterns,  59. 
Brads,  27. 

Brace  bit,  185. 

Brackets,  50. 

Building  up  thin  discs,  56. 

—patterns,  59,  61, 140. 
Brass,  shrinkage  of,  16. 

—  for  patterns,  23. 


Cause    of    distortion    in   cast- 
ings, 19. 

Castings,  distortion  of,   19. 
Casting  of  gland,  67. 

— of  double  flange  bush- 
ing, 77. 

— of  hook  lever,  49. 
—of  pulley,  93. 
— of  pipe  elbow,  129. 


—of  pipe  bend,  126. 

— of  steam   chest    cover, 

132. 
Cabinet  turning,  199. 

— making,  1. 

— maker,  1. 
Chords  of  curves,  61. 
Chucks,  122,  123,  201,  203. 
Chuck,  cup,  203. 

—fork,  201. 

—large,  123. 
Constructional  joints,  55. 
Copal  varnish,  26. 
Cores,  37. 
Core  box,  39,  41. 

—prints,  38,  40,  42,  44. 

— box,  finishing  of,  75. 

—board,   134. 

—strickle,  134. 

—box  plane,  72,  195. 

— box,  conical,  74. 
Cope,  6,  7,  10. 

—bars,  7. 

—sand,  8,  9. 
Contraction,  15. 
Concentric,  161. 

—layers,  161. 

—hubs  to  be,  105. 
Corners  in  patterns,  30. 

—inside,  30. 

—outside,  30. 
Counter  ribs,  57. 
Cylindrical  layers,  161. 

— patterns,  61. 

—cores,  39,  110 


INDEX 


213 


Distortion    in    castings,  cause 
of,  19. 

— caused  by  shrinkage,  18 
Dividers,  173. 

— laying  out  angles  with, 

173. 
Double  shrinkage  patterns,  23. 

— allowance  for,  23. 
Dirty  mold,  32. 
Drawings,  reading  of,  154. 
Draft  on  patterns,  13,  14. 
Diagonal  lines, 

E 

Engineer, requirements  of  the,  4 
End  wood,  25. 

— grain  to  be  sized,  25. 
Emery  wheels,  197. 

—for  grinding  tools,  197. 


Face  plate,  201. 

—plate  lathe.     (Frontis- 
piece.) 

Faces,  working,  189. 
Framing  square,  171. 
Fillet,  30. 
Fillets,  making,  33. 

— in      patterns,      reason 
for,  31. 

-leather,  32. 

-wood,  33. 

—wax,  34. 
Filing  saws,  179. 
Fitting  saws,  179. 


Gauge,  marking,  174. 


— mortise,  174. 
Gears,  108. 

—bevel,  120. 

—spur,  108. 

— the  laying  out  of,  111, 
113,  117,  120. 

— tooth  curves  for,  117. 

— patterns  for,  108. 

— patterns,  arms  for,  120. 

—patterns,  teeth  for,  118. 

— patterns,   tooth  blocks 

for,  113. 
Glue,  24. 

—joints,  24. 

—use  of,  24. 
Gouge,  175. 

—outside,  176. 

-inside,  176. 

—paring,  176. 

— turning,  204. 

Grindstone,  197. 

Grinding  cutting  wedges,  197. 

-chisel,  197. 

—plane  iron,  192. 


Hand  screw,  187. 
Handscrews,  use  of,  187. 
Handsaw,  178. 


Iron  planes,  190,  192. 
—castings,  2. 
— shrinkage  of,  16. 


Jointer  plane,  188. 
Joints   in    patterns  (construc- 
tional), 55, 


214 


INDEX 


—  in      patterns      (mold 
er's),  46. 


Knife,  draw,  177. 


Lags,  patterns  built  of,  60.  61. 
Lagging,  60. 
Lagging  up,  60. 
Loam,  133. 

—  patterns,  134. 
Leather  fillets,  32. 

—  the  application  of,  32. 
Lugs  for  machinist's  use,  140. 

M 

Making  pattern  pins,  79. 

—  semi  -  circular     core 
box,  70. 

—  pulley  patterns,  93 
Marking  gauge,  174. 
Master  patterns,  23,  151. 
Metals,  shrinkage  of,  16. 
Measuring  tools,  169. 
Mitre  square,  172. 
Mahogany,  22. 

Mortise  gauge,  174. 
Molding,  6. 
Mitre  box,  186. 

N 

Nails,     27 

Nails,  best  for  patterns,  27 

Nowel,  7. 


Oil  stones,  197. 
Open  joints,  58. 


Parting,  pattern-maker's,  77. 

— molder's,  9. 

Patterns,  construction  of,  66. 
Pattern-making    and    molding 
(connection   between), 
2,  3,5. 
Pattern  pins,  79. 

—wood  for,  20. 

—lathe,  54,  200. 
Pegging  segments,  99. 
Plane,  core  box,  72. 

—rebate,  193. 

—dado,   194. 

—plow,   193. 
Planes,  surfacing,  188. 

— combination,  194, 

—wood,  191. 

— iron,  190. 
Pins,  pattern,  79. 
Pulley,  pattern  for,  93. 

S 

Segments,  building  with,  61. 

Screwdriver,  185. 

Spoke  shave,  194,   195. 

Shrink  rule,  17. 

Shake,  allowance  for,  17. 

Sprue  pm,_9. 

Saws,  177. 

Saw,  hand,  178. 

—back,  178. 

—keyhole,  178. 

— compass,  178. 

—band,  82. 

— circular,  65. 
Scale  on  castings,   18. 
Scales  for  measuring,  170. 
Scrapers,  201,  205. 


INDEX 


215 


Scraping  a  surface,  209. 
Sap  side  of  board,  21,  166. 
Sandpaper,  23. 
Sandpapering  machine,  29. 
Shellac  varnish,  26. 
Shoot  board,  96. 
Shooting  joints,  96. 
Shrinkage  of  iron,  16. 

— of  brass,  16. 

—of  steel,  16. 

— of  aluminum,  16. 

—double,  23. 
Screws,  27. 

— in  end  wood,  28. 
Stove  pattern-making,  145. 
Strickles,   134. 
Square,  framing,  171. 

—try,  171. 

— combination,  172. 
Stone,  oil,  197. 
Surfacing  planes,   188. 

T 

Taper  on  patterns,  14. 
Tools  for  woodwork,  167. 
T  bevel,  172. 
Trimmer,  95,  98. 
Turning  lathe,  200. 

-tools,  204,  206. 


— cabinet,  1. 

—patterns,  199. 

— in  cup  chuck,  203. 

— parted  pattern,  80. 
Thin  discs,  building  of,  56. 
Thin  boards,  building  of,  56. 
Template,  111. 

V 

Varnish,  yellow,  26. 

—red,  26. 

—black,  26. 

Vertical  sides  of  patterns,  15. 
Vise,  pattern-maker's,  163. 

W 

Warp,  allowance  for,  18. 
Warping  in  wood,  165. 
— in  castings,  19. 
Wheels,  gear,  108. 

Wood,  drills,   183. 

—turner's  lathe,  200. 

— for  patterns,  20. 

—fillets,  forming  of,  33. 
Wheels,  gear,  108. 

— arms  of,  99. 
-teeth  of,  111.    ' 

-laying  out,  117,  121. 


7806 


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